picture_layer_impl.cc revision 35a176bd53e5064664fcec3833bc64667c636393 
1// Copyright 2012 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#include "cc/layers/picture_layer_impl.h"
6
7#include <algorithm>
8#include <limits>
9#include <set>
10
11#include "base/time/time.h"
12#include "cc/base/math_util.h"
13#include "cc/base/util.h"
14#include "cc/debug/debug_colors.h"
15#include "cc/debug/micro_benchmark_impl.h"
16#include "cc/debug/traced_value.h"
17#include "cc/layers/append_quads_data.h"
18#include "cc/layers/quad_sink.h"
19#include "cc/quads/checkerboard_draw_quad.h"
20#include "cc/quads/debug_border_draw_quad.h"
21#include "cc/quads/picture_draw_quad.h"
22#include "cc/quads/solid_color_draw_quad.h"
23#include "cc/quads/tile_draw_quad.h"
24#include "cc/resources/tile_manager.h"
25#include "cc/trees/layer_tree_impl.h"
26#include "ui/gfx/quad_f.h"
27#include "ui/gfx/rect_conversions.h"
28#include "ui/gfx/size_conversions.h"
29
30namespace {
31const float kMaxScaleRatioDuringPinch = 2.0f;
32
33// When creating a new tiling during pinch, snap to an existing
34// tiling's scale if the desired scale is within this ratio.
35const float kSnapToExistingTilingRatio = 1.2f;
36
37// Estimate skewport 60 frames ahead for pre-rasterization on the CPU.
38const float kCpuSkewportTargetTimeInFrames = 60.0f;
39
40// Don't pre-rasterize on the GPU (except for kBackflingGuardDistancePixels in
41// TileManager::BinFromTilePriority).
42const float kGpuSkewportTargetTimeInFrames = 0.0f;
43
44}  // namespace
45
46namespace cc {
47
48PictureLayerImpl::PictureLayerImpl(LayerTreeImpl* tree_impl, int id)
49    : LayerImpl(tree_impl, id),
50      twin_layer_(NULL),
51      pile_(PicturePileImpl::Create()),
52      is_mask_(false),
53      ideal_page_scale_(0.f),
54      ideal_device_scale_(0.f),
55      ideal_source_scale_(0.f),
56      ideal_contents_scale_(0.f),
57      raster_page_scale_(0.f),
58      raster_device_scale_(0.f),
59      raster_source_scale_(0.f),
60      raster_contents_scale_(0.f),
61      low_res_raster_contents_scale_(0.f),
62      raster_source_scale_is_fixed_(false),
63      was_screen_space_transform_animating_(false),
64      needs_post_commit_initialization_(true),
65      should_update_tile_priorities_(false) {
66  layer_tree_impl()->RegisterPictureLayerImpl(this);
67}
68
69PictureLayerImpl::~PictureLayerImpl() {
70  layer_tree_impl()->UnregisterPictureLayerImpl(this);
71}
72
73const char* PictureLayerImpl::LayerTypeAsString() const {
74  return "cc::PictureLayerImpl";
75}
76
77scoped_ptr<LayerImpl> PictureLayerImpl::CreateLayerImpl(
78    LayerTreeImpl* tree_impl) {
79  return PictureLayerImpl::Create(tree_impl, id()).PassAs<LayerImpl>();
80}
81
82void PictureLayerImpl::PushPropertiesTo(LayerImpl* base_layer) {
83  // It's possible this layer was never drawn or updated (e.g. because it was
84  // a descendant of an opacity 0 layer).
85  DoPostCommitInitializationIfNeeded();
86  PictureLayerImpl* layer_impl = static_cast<PictureLayerImpl*>(base_layer);
87
88  // We have already synced the important bits from the the active layer, and
89  // we will soon swap out its tilings and use them for recycling. However,
90  // there are now tiles in this layer's tilings that were unref'd and replaced
91  // with new tiles (due to invalidation). This resets all active priorities on
92  // the to-be-recycled tiling to ensure replaced tiles don't linger and take
93  // memory (due to a stale 'active' priority).
94  if (layer_impl->tilings_)
95    layer_impl->tilings_->DidBecomeRecycled();
96
97  LayerImpl::PushPropertiesTo(base_layer);
98
99  // When the pending tree pushes to the active tree, the pending twin
100  // becomes recycled.
101  layer_impl->twin_layer_ = NULL;
102  twin_layer_ = NULL;
103
104  layer_impl->SetIsMask(is_mask_);
105  layer_impl->pile_ = pile_;
106
107  // Tilings would be expensive to push, so we swap.
108  layer_impl->tilings_.swap(tilings_);
109
110  // Ensure that we don't have any tiles that are out of date.
111  if (tilings_)
112    tilings_->RemoveTilesInRegion(invalidation_);
113
114  layer_impl->tilings_->SetClient(layer_impl);
115  if (tilings_)
116    tilings_->SetClient(this);
117
118  layer_impl->raster_page_scale_ = raster_page_scale_;
119  layer_impl->raster_device_scale_ = raster_device_scale_;
120  layer_impl->raster_source_scale_ = raster_source_scale_;
121  layer_impl->raster_contents_scale_ = raster_contents_scale_;
122  layer_impl->low_res_raster_contents_scale_ = low_res_raster_contents_scale_;
123  layer_impl->needs_post_commit_initialization_ = false;
124
125  // The invalidation on this soon-to-be-recycled layer must be cleared to
126  // mirror clearing the invalidation in PictureLayer's version of this function
127  // in case push properties is skipped.
128  layer_impl->invalidation_.Swap(&invalidation_);
129  invalidation_.Clear();
130  needs_post_commit_initialization_ = true;
131
132  // We always need to push properties.
133  // See http://crbug.com/303943
134  needs_push_properties_ = true;
135}
136
137void PictureLayerImpl::AppendQuads(QuadSink* quad_sink,
138                                   AppendQuadsData* append_quads_data) {
139  DCHECK(!needs_post_commit_initialization_);
140
141  float max_contents_scale = MaximumTilingContentsScale();
142  gfx::Transform scaled_draw_transform = draw_transform();
143  scaled_draw_transform.Scale(SK_MScalar1 / max_contents_scale,
144                              SK_MScalar1 / max_contents_scale);
145  gfx::Size scaled_content_bounds =
146      gfx::ToCeiledSize(gfx::ScaleSize(content_bounds(), max_contents_scale));
147
148  gfx::Rect scaled_visible_content_rect =
149      gfx::ScaleToEnclosingRect(visible_content_rect(), max_contents_scale);
150  scaled_visible_content_rect.Intersect(gfx::Rect(scaled_content_bounds));
151
152  SharedQuadState* shared_quad_state = quad_sink->CreateSharedQuadState();
153  shared_quad_state->SetAll(scaled_draw_transform,
154                            scaled_content_bounds,
155                            scaled_visible_content_rect,
156                            draw_properties().clip_rect,
157                            draw_properties().is_clipped,
158                            draw_properties().opacity,
159                            blend_mode(),
160                            sorting_context_id_);
161
162  gfx::Rect rect = scaled_visible_content_rect;
163
164  if (current_draw_mode_ == DRAW_MODE_RESOURCELESS_SOFTWARE) {
165    AppendDebugBorderQuad(
166        quad_sink,
167        scaled_content_bounds,
168        shared_quad_state,
169        append_quads_data,
170        DebugColors::DirectPictureBorderColor(),
171        DebugColors::DirectPictureBorderWidth(layer_tree_impl()));
172
173    gfx::Rect geometry_rect = rect;
174    gfx::Rect opaque_rect = contents_opaque() ? geometry_rect : gfx::Rect();
175    gfx::Rect visible_geometry_rect =
176        quad_sink->UnoccludedContentRect(geometry_rect, scaled_draw_transform);
177    if (visible_geometry_rect.IsEmpty())
178      return;
179
180    gfx::Size texture_size = rect.size();
181    gfx::RectF texture_rect = gfx::RectF(texture_size);
182    gfx::Rect quad_content_rect = rect;
183
184    scoped_ptr<PictureDrawQuad> quad = PictureDrawQuad::Create();
185    quad->SetNew(shared_quad_state,
186                 geometry_rect,
187                 opaque_rect,
188                 visible_geometry_rect,
189                 texture_rect,
190                 texture_size,
191                 RGBA_8888,
192                 quad_content_rect,
193                 max_contents_scale,
194                 pile_);
195    quad_sink->Append(quad.PassAs<DrawQuad>());
196    append_quads_data->num_missing_tiles++;
197    return;
198  }
199
200  AppendDebugBorderQuad(
201      quad_sink, scaled_content_bounds, shared_quad_state, append_quads_data);
202
203  if (ShowDebugBorders()) {
204    for (PictureLayerTilingSet::CoverageIterator iter(
205             tilings_.get(), max_contents_scale, rect, ideal_contents_scale_);
206         iter;
207         ++iter) {
208      SkColor color;
209      float width;
210      if (*iter && iter->IsReadyToDraw()) {
211        ManagedTileState::TileVersion::Mode mode =
212            iter->GetTileVersionForDrawing().mode();
213        if (mode == ManagedTileState::TileVersion::SOLID_COLOR_MODE) {
214          color = DebugColors::SolidColorTileBorderColor();
215          width = DebugColors::SolidColorTileBorderWidth(layer_tree_impl());
216        } else if (mode == ManagedTileState::TileVersion::PICTURE_PILE_MODE) {
217          color = DebugColors::PictureTileBorderColor();
218          width = DebugColors::PictureTileBorderWidth(layer_tree_impl());
219        } else if (iter->priority(ACTIVE_TREE).resolution == HIGH_RESOLUTION) {
220          color = DebugColors::HighResTileBorderColor();
221          width = DebugColors::HighResTileBorderWidth(layer_tree_impl());
222        } else if (iter->priority(ACTIVE_TREE).resolution == LOW_RESOLUTION) {
223          color = DebugColors::LowResTileBorderColor();
224          width = DebugColors::LowResTileBorderWidth(layer_tree_impl());
225        } else if (iter->contents_scale() > max_contents_scale) {
226          color = DebugColors::ExtraHighResTileBorderColor();
227          width = DebugColors::ExtraHighResTileBorderWidth(layer_tree_impl());
228        } else {
229          color = DebugColors::ExtraLowResTileBorderColor();
230          width = DebugColors::ExtraLowResTileBorderWidth(layer_tree_impl());
231        }
232      } else {
233        color = DebugColors::MissingTileBorderColor();
234        width = DebugColors::MissingTileBorderWidth(layer_tree_impl());
235      }
236
237      scoped_ptr<DebugBorderDrawQuad> debug_border_quad =
238          DebugBorderDrawQuad::Create();
239      gfx::Rect geometry_rect = iter.geometry_rect();
240      gfx::Rect visible_geometry_rect = geometry_rect;
241      debug_border_quad->SetNew(shared_quad_state,
242                                geometry_rect,
243                                visible_geometry_rect,
244                                color,
245                                width);
246      quad_sink->Append(debug_border_quad.PassAs<DrawQuad>());
247    }
248  }
249
250  // Keep track of the tilings that were used so that tilings that are
251  // unused can be considered for removal.
252  std::vector<PictureLayerTiling*> seen_tilings;
253
254  // Ignore missing tiles outside of viewport for tile priority. This is
255  // normally the same as draw viewport but can be independently overridden by
256  // embedders like Android WebView with SetExternalDrawConstraints.
257  gfx::Rect scaled_viewport_for_tile_priority = gfx::ScaleToEnclosingRect(
258      GetViewportForTilePriorityInContentSpace(), max_contents_scale);
259
260  size_t missing_tile_count = 0u;
261  size_t on_demand_missing_tile_count = 0u;
262  for (PictureLayerTilingSet::CoverageIterator iter(
263           tilings_.get(), max_contents_scale, rect, ideal_contents_scale_);
264       iter;
265       ++iter) {
266    gfx::Rect geometry_rect = iter.geometry_rect();
267    gfx::Rect visible_geometry_rect =
268        quad_sink->UnoccludedContentRect(geometry_rect, scaled_draw_transform);
269    if (visible_geometry_rect.IsEmpty())
270      continue;
271
272    append_quads_data->visible_content_area +=
273        visible_geometry_rect.width() * visible_geometry_rect.height();
274
275    scoped_ptr<DrawQuad> draw_quad;
276    if (*iter && iter->IsReadyToDraw()) {
277      const ManagedTileState::TileVersion& tile_version =
278          iter->GetTileVersionForDrawing();
279      switch (tile_version.mode()) {
280        case ManagedTileState::TileVersion::RESOURCE_MODE: {
281          gfx::RectF texture_rect = iter.texture_rect();
282          gfx::Rect opaque_rect = iter->opaque_rect();
283          opaque_rect.Intersect(geometry_rect);
284
285          if (iter->contents_scale() != ideal_contents_scale_ &&
286              geometry_rect.Intersects(scaled_viewport_for_tile_priority)) {
287            append_quads_data->had_incomplete_tile = true;
288          }
289
290          scoped_ptr<TileDrawQuad> quad = TileDrawQuad::Create();
291          quad->SetNew(shared_quad_state,
292                       geometry_rect,
293                       opaque_rect,
294                       visible_geometry_rect,
295                       tile_version.get_resource_id(),
296                       texture_rect,
297                       iter.texture_size(),
298                       tile_version.contents_swizzled());
299          draw_quad = quad.PassAs<DrawQuad>();
300          break;
301        }
302        case ManagedTileState::TileVersion::PICTURE_PILE_MODE: {
303          if (!layer_tree_impl()
304                   ->GetRendererCapabilities()
305                   .allow_rasterize_on_demand) {
306            ++on_demand_missing_tile_count;
307            break;
308          }
309
310          gfx::RectF texture_rect = iter.texture_rect();
311          gfx::Rect opaque_rect = iter->opaque_rect();
312          opaque_rect.Intersect(geometry_rect);
313
314          ResourceProvider* resource_provider =
315              layer_tree_impl()->resource_provider();
316          ResourceFormat format =
317              resource_provider->memory_efficient_texture_format();
318          scoped_ptr<PictureDrawQuad> quad = PictureDrawQuad::Create();
319          quad->SetNew(shared_quad_state,
320                       geometry_rect,
321                       opaque_rect,
322                       visible_geometry_rect,
323                       texture_rect,
324                       iter.texture_size(),
325                       format,
326                       iter->content_rect(),
327                       iter->contents_scale(),
328                       pile_);
329          draw_quad = quad.PassAs<DrawQuad>();
330          break;
331        }
332        case ManagedTileState::TileVersion::SOLID_COLOR_MODE: {
333          scoped_ptr<SolidColorDrawQuad> quad = SolidColorDrawQuad::Create();
334          quad->SetNew(shared_quad_state,
335                       geometry_rect,
336                       visible_geometry_rect,
337                       tile_version.get_solid_color(),
338                       false);
339          draw_quad = quad.PassAs<DrawQuad>();
340          break;
341        }
342      }
343    }
344
345    if (!draw_quad) {
346      if (draw_checkerboard_for_missing_tiles()) {
347        scoped_ptr<CheckerboardDrawQuad> quad = CheckerboardDrawQuad::Create();
348        SkColor color = DebugColors::DefaultCheckerboardColor();
349        quad->SetNew(
350            shared_quad_state, geometry_rect, visible_geometry_rect, color);
351        quad_sink->Append(quad.PassAs<DrawQuad>());
352      } else {
353        SkColor color = SafeOpaqueBackgroundColor();
354        scoped_ptr<SolidColorDrawQuad> quad = SolidColorDrawQuad::Create();
355        quad->SetNew(shared_quad_state,
356                     geometry_rect,
357                     visible_geometry_rect,
358                     color,
359                     false);
360        quad_sink->Append(quad.PassAs<DrawQuad>());
361      }
362
363      if (geometry_rect.Intersects(scaled_viewport_for_tile_priority)) {
364        append_quads_data->num_missing_tiles++;
365        append_quads_data->had_incomplete_tile = true;
366        ++missing_tile_count;
367      }
368      append_quads_data->approximated_visible_content_area +=
369          visible_geometry_rect.width() * visible_geometry_rect.height();
370      continue;
371    }
372
373    quad_sink->Append(draw_quad.Pass());
374
375    if (iter->priority(ACTIVE_TREE).resolution != HIGH_RESOLUTION) {
376      append_quads_data->approximated_visible_content_area +=
377          visible_geometry_rect.width() * visible_geometry_rect.height();
378    }
379
380    if (seen_tilings.empty() || seen_tilings.back() != iter.CurrentTiling())
381      seen_tilings.push_back(iter.CurrentTiling());
382  }
383
384  if (missing_tile_count) {
385    TRACE_EVENT_INSTANT2("cc",
386                         "PictureLayerImpl::AppendQuads checkerboard",
387                         TRACE_EVENT_SCOPE_THREAD,
388                         "missing_tile_count",
389                         missing_tile_count,
390                         "on_demand_missing_tile_count",
391                         on_demand_missing_tile_count);
392  }
393
394  // Aggressively remove any tilings that are not seen to save memory. Note
395  // that this is at the expense of doing cause more frequent re-painting. A
396  // better scheme would be to maintain a tighter visible_content_rect for the
397  // finer tilings.
398  CleanUpTilingsOnActiveLayer(seen_tilings);
399}
400
401void PictureLayerImpl::UpdateTiles() {
402  TRACE_EVENT0("cc", "PictureLayerImpl::UpdateTiles");
403
404  DoPostCommitInitializationIfNeeded();
405
406  // Transforms and viewport are invalid for tile management inside a
407  // resourceless software draw, so don't update them.
408  if (!layer_tree_impl()->resourceless_software_draw()) {
409    visible_rect_for_tile_priority_ = visible_content_rect();
410    viewport_rect_for_tile_priority_ =
411        layer_tree_impl()->ViewportRectForTilePriority();
412    screen_space_transform_for_tile_priority_ = screen_space_transform();
413  }
414
415  if (!CanHaveTilings()) {
416    ideal_page_scale_ = 0.f;
417    ideal_device_scale_ = 0.f;
418    ideal_contents_scale_ = 0.f;
419    ideal_source_scale_ = 0.f;
420    SanityCheckTilingState();
421    return;
422  }
423
424  UpdateIdealScales();
425
426  DCHECK(tilings_->num_tilings() > 0 || raster_contents_scale_ == 0.f)
427      << "A layer with no tilings shouldn't have valid raster scales";
428  if (!raster_contents_scale_ || ShouldAdjustRasterScale()) {
429    RecalculateRasterScales();
430    AddTilingsForRasterScale();
431  }
432
433  DCHECK(raster_page_scale_);
434  DCHECK(raster_device_scale_);
435  DCHECK(raster_source_scale_);
436  DCHECK(raster_contents_scale_);
437  DCHECK(low_res_raster_contents_scale_);
438
439  was_screen_space_transform_animating_ =
440      draw_properties().screen_space_transform_is_animating;
441
442  // TODO(sohanjg): Avoid needlessly update priorities when syncing to a
443  // non-updated tree which will then be updated immediately afterwards.
444  should_update_tile_priorities_ = true;
445
446  UpdateTilePriorities();
447
448  if (layer_tree_impl()->IsPendingTree())
449    MarkVisibleResourcesAsRequired();
450}
451
452void PictureLayerImpl::UpdateTilePriorities() {
453  TRACE_EVENT0("cc", "PictureLayerImpl::UpdateTilePriorities");
454
455  double current_frame_time_in_seconds =
456      (layer_tree_impl()->CurrentFrameTimeTicks() -
457       base::TimeTicks()).InSecondsF();
458
459  bool tiling_needs_update = false;
460  for (size_t i = 0; i < tilings_->num_tilings(); ++i) {
461    if (tilings_->tiling_at(i)->NeedsUpdateForFrameAtTime(
462            current_frame_time_in_seconds)) {
463      tiling_needs_update = true;
464      break;
465    }
466  }
467  if (!tiling_needs_update)
468    return;
469
470  gfx::Rect visible_rect_in_content_space(
471      GetViewportForTilePriorityInContentSpace());
472  visible_rect_in_content_space.Intersect(visible_rect_for_tile_priority_);
473  gfx::Rect visible_layer_rect = gfx::ScaleToEnclosingRect(
474      visible_rect_in_content_space, 1.f / contents_scale_x());
475  WhichTree tree =
476      layer_tree_impl()->IsActiveTree() ? ACTIVE_TREE : PENDING_TREE;
477  for (size_t i = 0; i < tilings_->num_tilings(); ++i) {
478    // TODO(sohanjg): Passing MaximumContentsScale as layer contents scale
479    // in UpdateTilePriorities is wrong and should be ideal contents scale.
480    tilings_->tiling_at(i)->UpdateTilePriorities(tree,
481                                                 visible_layer_rect,
482                                                 MaximumTilingContentsScale(),
483                                                 current_frame_time_in_seconds);
484  }
485
486  // Tile priorities were modified.
487  layer_tree_impl()->DidModifyTilePriorities();
488}
489
490gfx::Rect PictureLayerImpl::GetViewportForTilePriorityInContentSpace() const {
491  // If visible_rect_for_tile_priority_ is empty or
492  // viewport_rect_for_tile_priority_ is set to be different from the device
493  // viewport, try to inverse project the viewport into layer space and use
494  // that. Otherwise just use visible_rect_for_tile_priority_
495  gfx::Rect visible_rect_in_content_space = visible_rect_for_tile_priority_;
496
497  if (visible_rect_in_content_space.IsEmpty() ||
498      layer_tree_impl()->DeviceViewport() != viewport_rect_for_tile_priority_) {
499    gfx::Transform view_to_layer(gfx::Transform::kSkipInitialization);
500
501    if (screen_space_transform_for_tile_priority_.GetInverse(&view_to_layer)) {
502      // Transform from view space to content space.
503      visible_rect_in_content_space =
504          gfx::ToEnclosingRect(MathUtil::ProjectClippedRect(
505              view_to_layer, viewport_rect_for_tile_priority_));
506
507      visible_rect_in_content_space.Intersect(gfx::Rect(content_bounds()));
508    }
509  }
510
511  return visible_rect_in_content_space;
512}
513
514PictureLayerImpl* PictureLayerImpl::GetRecycledTwinLayer() {
515  // TODO(vmpstr): Maintain recycled twin as a member. crbug.com/407418
516  return static_cast<PictureLayerImpl*>(
517      layer_tree_impl()->FindRecycleTreeLayerById(id()));
518}
519
520void PictureLayerImpl::NotifyTileStateChanged(const Tile* tile) {
521  if (layer_tree_impl()->IsActiveTree()) {
522    gfx::RectF layer_damage_rect =
523        gfx::ScaleRect(tile->content_rect(), 1.f / tile->contents_scale());
524    AddDamageRect(layer_damage_rect);
525  }
526}
527
528void PictureLayerImpl::DidBecomeActive() {
529  LayerImpl::DidBecomeActive();
530  tilings_->DidBecomeActive();
531  layer_tree_impl()->DidModifyTilePriorities();
532}
533
534void PictureLayerImpl::DidBeginTracing() {
535  pile_->DidBeginTracing();
536}
537
538void PictureLayerImpl::ReleaseResources() {
539  if (tilings_)
540    RemoveAllTilings();
541
542  ResetRasterScale();
543
544  // To avoid an edge case after lost context where the tree is up to date but
545  // the tilings have not been managed, request an update draw properties
546  // to force tilings to get managed.
547  layer_tree_impl()->set_needs_update_draw_properties();
548}
549
550skia::RefPtr<SkPicture> PictureLayerImpl::GetPicture() {
551  return pile_->GetFlattenedPicture();
552}
553
554scoped_refptr<Tile> PictureLayerImpl::CreateTile(PictureLayerTiling* tiling,
555                                               const gfx::Rect& content_rect) {
556  if (!pile_->CanRaster(tiling->contents_scale(), content_rect))
557    return scoped_refptr<Tile>();
558
559  // TODO(vmpstr): Revisit this. For now, enabling analysis means that we get as
560  // much savings on memory as we can. However, for some cases like ganesh or
561  // small layers, the amount of time we spend analyzing might not justify
562  // memory savings that we can get.
563  // Bugs: crbug.com/397198, crbug.com/396908
564  int flags = Tile::USE_PICTURE_ANALYSIS;
565
566  return layer_tree_impl()->tile_manager()->CreateTile(
567      pile_.get(),
568      content_rect.size(),
569      content_rect,
570      contents_opaque() ? content_rect : gfx::Rect(),
571      tiling->contents_scale(),
572      id(),
573      layer_tree_impl()->source_frame_number(),
574      flags);
575}
576
577void PictureLayerImpl::UpdatePile(Tile* tile) {
578  tile->set_picture_pile(pile_);
579}
580
581const Region* PictureLayerImpl::GetInvalidation() {
582  return &invalidation_;
583}
584
585const PictureLayerTiling* PictureLayerImpl::GetTwinTiling(
586    const PictureLayerTiling* tiling) const {
587  if (!twin_layer_)
588    return NULL;
589  for (size_t i = 0; i < twin_layer_->tilings_->num_tilings(); ++i)
590    if (twin_layer_->tilings_->tiling_at(i)->contents_scale() ==
591        tiling->contents_scale())
592      return twin_layer_->tilings_->tiling_at(i);
593  return NULL;
594}
595
596PictureLayerTiling* PictureLayerImpl::GetRecycledTwinTiling(
597    const PictureLayerTiling* tiling) {
598  PictureLayerImpl* recycled_twin = GetRecycledTwinLayer();
599  if (!recycled_twin || !recycled_twin->tilings_)
600    return NULL;
601  return recycled_twin->tilings_->TilingAtScale(tiling->contents_scale());
602}
603
604size_t PictureLayerImpl::GetMaxTilesForInterestArea() const {
605  return layer_tree_impl()->settings().max_tiles_for_interest_area;
606}
607
608float PictureLayerImpl::GetSkewportTargetTimeInSeconds() const {
609  float skewport_target_time_in_frames =
610      layer_tree_impl()->use_gpu_rasterization()
611          ? kGpuSkewportTargetTimeInFrames
612          : kCpuSkewportTargetTimeInFrames;
613  return skewport_target_time_in_frames *
614         layer_tree_impl()->begin_impl_frame_interval().InSecondsF() *
615         layer_tree_impl()->settings().skewport_target_time_multiplier;
616}
617
618int PictureLayerImpl::GetSkewportExtrapolationLimitInContentPixels() const {
619  return layer_tree_impl()
620      ->settings()
621      .skewport_extrapolation_limit_in_content_pixels;
622}
623
624gfx::Size PictureLayerImpl::CalculateTileSize(
625    const gfx::Size& content_bounds) const {
626  if (is_mask_) {
627    int max_size = layer_tree_impl()->MaxTextureSize();
628    return gfx::Size(
629        std::min(max_size, content_bounds.width()),
630        std::min(max_size, content_bounds.height()));
631  }
632
633  int max_texture_size =
634      layer_tree_impl()->resource_provider()->max_texture_size();
635
636  gfx::Size default_tile_size = layer_tree_impl()->settings().default_tile_size;
637  if (layer_tree_impl()->use_gpu_rasterization()) {
638    // TODO(ernstm) crbug.com/365877: We need a unified way to override the
639    // default-tile-size.
640    default_tile_size =
641        gfx::Size(layer_tree_impl()->device_viewport_size().width(),
642                  layer_tree_impl()->device_viewport_size().height() / 4);
643  }
644  default_tile_size.SetToMin(gfx::Size(max_texture_size, max_texture_size));
645
646  gfx::Size max_untiled_content_size =
647      layer_tree_impl()->settings().max_untiled_layer_size;
648  max_untiled_content_size.SetToMin(
649      gfx::Size(max_texture_size, max_texture_size));
650
651  bool any_dimension_too_large =
652      content_bounds.width() > max_untiled_content_size.width() ||
653      content_bounds.height() > max_untiled_content_size.height();
654
655  bool any_dimension_one_tile =
656      content_bounds.width() <= default_tile_size.width() ||
657      content_bounds.height() <= default_tile_size.height();
658
659  // If long and skinny, tile at the max untiled content size, and clamp
660  // the smaller dimension to the content size, e.g. 1000x12 layer with
661  // 500x500 max untiled size would get 500x12 tiles.  Also do this
662  // if the layer is small.
663  if (any_dimension_one_tile || !any_dimension_too_large) {
664    int width = std::min(
665        std::max(max_untiled_content_size.width(), default_tile_size.width()),
666        content_bounds.width());
667    int height = std::min(
668        std::max(max_untiled_content_size.height(), default_tile_size.height()),
669        content_bounds.height());
670    // Round width and height up to the closest multiple of 64, or 56 if
671    // we should avoid power-of-two textures. This helps reduce the number
672    // of different textures sizes to help recycling, and also keeps all
673    // textures multiple-of-eight, which is preferred on some drivers (IMG).
674    bool avoid_pow2 =
675        layer_tree_impl()->GetRendererCapabilities().avoid_pow2_textures;
676    int round_up_to = avoid_pow2 ? 56 : 64;
677    width = RoundUp(width, round_up_to);
678    height = RoundUp(height, round_up_to);
679    return gfx::Size(width, height);
680  }
681
682  return default_tile_size;
683}
684
685void PictureLayerImpl::SyncFromActiveLayer(const PictureLayerImpl* other) {
686  TRACE_EVENT0("cc", "SyncFromActiveLayer");
687  DCHECK(!other->needs_post_commit_initialization_);
688  DCHECK(other->tilings_);
689
690  if (!DrawsContent()) {
691    RemoveAllTilings();
692    return;
693  }
694
695  raster_page_scale_ = other->raster_page_scale_;
696  raster_device_scale_ = other->raster_device_scale_;
697  raster_source_scale_ = other->raster_source_scale_;
698  raster_contents_scale_ = other->raster_contents_scale_;
699  low_res_raster_contents_scale_ = other->low_res_raster_contents_scale_;
700
701  // Union in the other newly exposed regions as invalid.
702  Region difference_region = Region(gfx::Rect(bounds()));
703  difference_region.Subtract(gfx::Rect(other->bounds()));
704  invalidation_.Union(difference_region);
705
706  bool synced_high_res_tiling = false;
707  if (CanHaveTilings()) {
708    synced_high_res_tiling = tilings_->SyncTilings(
709        *other->tilings_, bounds(), invalidation_, MinimumContentsScale());
710  } else {
711    RemoveAllTilings();
712  }
713
714  // If our MinimumContentsScale has changed to prevent the twin's high res
715  // tiling from being synced, we should reset the raster scale and let it be
716  // recalculated (1) again. This can happen if our bounds shrink to the point
717  // where min contents scale grows.
718  // (1) - TODO(vmpstr) Instead of hoping that this will be recalculated, we
719  // should refactor this code a little bit and actually recalculate this.
720  // However, this is a larger undertaking, so this will work for now.
721  if (!synced_high_res_tiling)
722    ResetRasterScale();
723  else
724    SanityCheckTilingState();
725}
726
727void PictureLayerImpl::SyncTiling(
728    const PictureLayerTiling* tiling) {
729  if (!CanHaveTilingWithScale(tiling->contents_scale()))
730    return;
731  tilings_->AddTiling(tiling->contents_scale());
732
733  // If this tree needs update draw properties, then the tiling will
734  // get updated prior to drawing or activation.  If this tree does not
735  // need update draw properties, then its transforms are up to date and
736  // we can create tiles for this tiling immediately.
737  if (!layer_tree_impl()->needs_update_draw_properties() &&
738      should_update_tile_priorities_) {
739    UpdateTilePriorities();
740  }
741}
742
743void PictureLayerImpl::SetIsMask(bool is_mask) {
744  if (is_mask_ == is_mask)
745    return;
746  is_mask_ = is_mask;
747  if (tilings_)
748    tilings_->RemoveAllTiles();
749}
750
751ResourceProvider::ResourceId PictureLayerImpl::ContentsResourceId() const {
752  gfx::Rect content_rect(content_bounds());
753  float scale = MaximumTilingContentsScale();
754  PictureLayerTilingSet::CoverageIterator iter(
755      tilings_.get(), scale, content_rect, ideal_contents_scale_);
756
757  // Mask resource not ready yet.
758  if (!iter || !*iter)
759    return 0;
760
761  // Masks only supported if they fit on exactly one tile.
762  if (iter.geometry_rect() != content_rect)
763    return 0;
764
765  const ManagedTileState::TileVersion& tile_version =
766      iter->GetTileVersionForDrawing();
767  if (!tile_version.IsReadyToDraw() ||
768      tile_version.mode() != ManagedTileState::TileVersion::RESOURCE_MODE)
769    return 0;
770
771  return tile_version.get_resource_id();
772}
773
774void PictureLayerImpl::MarkVisibleResourcesAsRequired() const {
775  DCHECK(layer_tree_impl()->IsPendingTree());
776  DCHECK(ideal_contents_scale_);
777  DCHECK_GT(tilings_->num_tilings(), 0u);
778
779  // The goal of this function is to find the minimum set of tiles that need to
780  // be ready to draw in order to activate without flashing content from a
781  // higher res on the active tree to a lower res on the pending tree.
782
783  // First, early out for layers with no visible content.
784  if (visible_rect_for_tile_priority_.IsEmpty())
785    return;
786
787  gfx::Rect rect(visible_rect_for_tile_priority_);
788
789  // Only mark tiles inside the viewport for tile priority as required for
790  // activation. This viewport is normally the same as the draw viewport but
791  // can be independently overridden by embedders like Android WebView with
792  // SetExternalDrawConstraints.
793  rect.Intersect(GetViewportForTilePriorityInContentSpace());
794
795  float min_acceptable_scale =
796      std::min(raster_contents_scale_, ideal_contents_scale_);
797
798  if (PictureLayerImpl* twin = twin_layer_) {
799    float twin_min_acceptable_scale =
800        std::min(twin->ideal_contents_scale_, twin->raster_contents_scale_);
801    // Ignore 0 scale in case CalculateContentsScale() has never been
802    // called for active twin.
803    if (twin_min_acceptable_scale != 0.0f) {
804      min_acceptable_scale =
805          std::min(min_acceptable_scale, twin_min_acceptable_scale);
806    }
807  }
808
809  PictureLayerTiling* high_res = NULL;
810  PictureLayerTiling* low_res = NULL;
811
812  // First pass: ready to draw tiles in acceptable but non-ideal tilings are
813  // marked as required for activation so that their textures are not thrown
814  // away; any non-ready tiles are not marked as required.
815  Region missing_region = rect;
816  for (size_t i = 0; i < tilings_->num_tilings(); ++i) {
817    PictureLayerTiling* tiling = tilings_->tiling_at(i);
818    DCHECK(tiling->has_ever_been_updated());
819
820    if (tiling->resolution() == LOW_RESOLUTION) {
821      DCHECK(!low_res) << "There can only be one low res tiling";
822      low_res = tiling;
823    }
824    if (tiling->contents_scale() < min_acceptable_scale)
825      continue;
826    if (tiling->resolution() == HIGH_RESOLUTION) {
827      DCHECK(!high_res) << "There can only be one high res tiling";
828      high_res = tiling;
829      continue;
830    }
831    for (PictureLayerTiling::CoverageIterator iter(tiling,
832                                                   contents_scale_x(),
833                                                   rect);
834         iter;
835         ++iter) {
836      if (!*iter || !iter->IsReadyToDraw())
837        continue;
838
839      missing_region.Subtract(iter.geometry_rect());
840      iter->MarkRequiredForActivation();
841    }
842  }
843  DCHECK(high_res) << "There must be one high res tiling";
844
845  // If these pointers are null (because no twin, no matching tiling, or the
846  // simpification just below), then high res tiles will be required to fill any
847  // holes left by the first pass above.  If the pointers are valid, then this
848  // layer is allowed to skip any tiles that are not ready on its twin.
849  const PictureLayerTiling* twin_high_res = NULL;
850  const PictureLayerTiling* twin_low_res = NULL;
851
852  if (twin_layer_) {
853    // As a simplification, only allow activating to skip twin tiles that the
854    // active layer is also missing when both this layer and its twin have
855    // "simple" sets of tilings: only 2 tilings (high and low) or only 1 high
856    // res tiling. This avoids having to iterate/track coverage of non-ideal
857    // tilings during the last draw call on the active layer.
858    if (tilings_->num_tilings() <= 2 &&
859        twin_layer_->tilings_->num_tilings() <= tilings_->num_tilings()) {
860      twin_low_res = low_res ? GetTwinTiling(low_res) : NULL;
861      twin_high_res = high_res ? GetTwinTiling(high_res) : NULL;
862    }
863
864    // If this layer and its twin have different transforms, then don't compare
865    // them and only allow activating to high res tiles, since tiles on each
866    // layer will be in different places on screen.
867    if (twin_layer_->layer_tree_impl()->RequiresHighResToDraw() ||
868        bounds() != twin_layer_->bounds() ||
869        draw_properties().screen_space_transform !=
870            twin_layer_->draw_properties().screen_space_transform) {
871      twin_high_res = NULL;
872      twin_low_res = NULL;
873    }
874  }
875
876  // As a second pass, mark as required any visible high res tiles not filled in
877  // by acceptable non-ideal tiles from the first pass.
878  if (MarkVisibleTilesAsRequired(
879      high_res, twin_high_res, contents_scale_x(), rect, missing_region)) {
880    // As an optional third pass, if a high res tile was skipped because its
881    // twin was also missing, then fall back to mark low res tiles as required
882    // in case the active twin is substituting those for missing high res
883    // content. Only suitable, when low res is enabled.
884    if (low_res) {
885      MarkVisibleTilesAsRequired(
886          low_res, twin_low_res, contents_scale_x(), rect, missing_region);
887    }
888  }
889}
890
891bool PictureLayerImpl::MarkVisibleTilesAsRequired(
892    PictureLayerTiling* tiling,
893    const PictureLayerTiling* optional_twin_tiling,
894    float contents_scale,
895    const gfx::Rect& rect,
896    const Region& missing_region) const {
897  bool twin_had_missing_tile = false;
898  for (PictureLayerTiling::CoverageIterator iter(tiling,
899                                                 contents_scale,
900                                                 rect);
901       iter;
902       ++iter) {
903    Tile* tile = *iter;
904    // A null tile (i.e. missing recording) can just be skipped.
905    if (!tile)
906      continue;
907
908    // If the missing region doesn't cover it, this tile is fully
909    // covered by acceptable tiles at other scales.
910    if (!missing_region.Intersects(iter.geometry_rect()))
911      continue;
912
913    // If the twin tile doesn't exist (i.e. missing recording or so far away
914    // that it is outside the visible tile rect) or this tile is shared between
915    // with the twin, then this tile isn't required to prevent flashing.
916    if (optional_twin_tiling) {
917      Tile* twin_tile = optional_twin_tiling->TileAt(iter.i(), iter.j());
918      if (!twin_tile || twin_tile == tile) {
919        twin_had_missing_tile = true;
920        continue;
921      }
922    }
923
924    tile->MarkRequiredForActivation();
925  }
926  return twin_had_missing_tile;
927}
928
929void PictureLayerImpl::DoPostCommitInitialization() {
930  DCHECK(needs_post_commit_initialization_);
931  DCHECK(layer_tree_impl()->IsPendingTree());
932
933  if (!tilings_)
934    tilings_.reset(new PictureLayerTilingSet(this, bounds()));
935
936  DCHECK(!twin_layer_);
937  twin_layer_ = static_cast<PictureLayerImpl*>(
938      layer_tree_impl()->FindActiveTreeLayerById(id()));
939  if (twin_layer_) {
940    DCHECK(!twin_layer_->twin_layer_);
941    twin_layer_->twin_layer_ = this;
942    // If the twin has never been pushed to, do not sync from it.
943    // This can happen if this function is called during activation.
944    if (!twin_layer_->needs_post_commit_initialization_)
945      SyncFromActiveLayer(twin_layer_);
946  }
947
948  needs_post_commit_initialization_ = false;
949}
950
951PictureLayerTiling* PictureLayerImpl::AddTiling(float contents_scale) {
952  DCHECK(CanHaveTilingWithScale(contents_scale)) <<
953      "contents_scale: " << contents_scale;
954
955  PictureLayerTiling* tiling = tilings_->AddTiling(contents_scale);
956
957  DCHECK(pile_->HasRecordings());
958
959  if (twin_layer_)
960    twin_layer_->SyncTiling(tiling);
961
962  return tiling;
963}
964
965void PictureLayerImpl::RemoveTiling(float contents_scale) {
966  if (!tilings_ || tilings_->num_tilings() == 0)
967    return;
968
969  for (size_t i = 0; i < tilings_->num_tilings(); ++i) {
970    PictureLayerTiling* tiling = tilings_->tiling_at(i);
971    if (tiling->contents_scale() == contents_scale) {
972      tilings_->Remove(tiling);
973      break;
974    }
975  }
976  if (tilings_->num_tilings() == 0)
977    ResetRasterScale();
978  SanityCheckTilingState();
979}
980
981void PictureLayerImpl::RemoveAllTilings() {
982  if (tilings_)
983    tilings_->RemoveAllTilings();
984  // If there are no tilings, then raster scales are no longer meaningful.
985  ResetRasterScale();
986}
987
988namespace {
989
990inline float PositiveRatio(float float1, float float2) {
991  DCHECK_GT(float1, 0);
992  DCHECK_GT(float2, 0);
993  return float1 > float2 ? float1 / float2 : float2 / float1;
994}
995
996}  // namespace
997
998void PictureLayerImpl::AddTilingsForRasterScale() {
999  PictureLayerTiling* high_res = NULL;
1000  PictureLayerTiling* low_res = NULL;
1001
1002  PictureLayerTiling* previous_low_res = NULL;
1003  for (size_t i = 0; i < tilings_->num_tilings(); ++i) {
1004    PictureLayerTiling* tiling = tilings_->tiling_at(i);
1005    if (tiling->contents_scale() == raster_contents_scale_)
1006      high_res = tiling;
1007    if (tiling->contents_scale() == low_res_raster_contents_scale_)
1008      low_res = tiling;
1009    if (tiling->resolution() == LOW_RESOLUTION)
1010      previous_low_res = tiling;
1011
1012    // Reset all tilings to non-ideal until the end of this function.
1013    tiling->set_resolution(NON_IDEAL_RESOLUTION);
1014  }
1015
1016  if (!high_res) {
1017    high_res = AddTiling(raster_contents_scale_);
1018    if (raster_contents_scale_ == low_res_raster_contents_scale_)
1019      low_res = high_res;
1020  }
1021
1022  // Only create new low res tilings when the transform is static.  This
1023  // prevents wastefully creating a paired low res tiling for every new high res
1024  // tiling during a pinch or a CSS animation.
1025  bool is_pinching = layer_tree_impl()->PinchGestureActive();
1026  if (layer_tree_impl()->create_low_res_tiling() && !is_pinching &&
1027      !draw_properties().screen_space_transform_is_animating && !low_res &&
1028      low_res != high_res)
1029    low_res = AddTiling(low_res_raster_contents_scale_);
1030
1031  // Set low-res if we have one.
1032  if (!low_res)
1033    low_res = previous_low_res;
1034  if (low_res && low_res != high_res)
1035    low_res->set_resolution(LOW_RESOLUTION);
1036
1037  // Make sure we always have one high-res (even if high == low).
1038  high_res->set_resolution(HIGH_RESOLUTION);
1039
1040  SanityCheckTilingState();
1041}
1042
1043bool PictureLayerImpl::ShouldAdjustRasterScale() const {
1044  if (was_screen_space_transform_animating_ !=
1045      draw_properties().screen_space_transform_is_animating)
1046    return true;
1047
1048  bool is_pinching = layer_tree_impl()->PinchGestureActive();
1049  if (is_pinching && raster_page_scale_) {
1050    // We change our raster scale when it is:
1051    // - Higher than ideal (need a lower-res tiling available)
1052    // - Too far from ideal (need a higher-res tiling available)
1053    float ratio = ideal_page_scale_ / raster_page_scale_;
1054    if (raster_page_scale_ > ideal_page_scale_ ||
1055        ratio > kMaxScaleRatioDuringPinch)
1056      return true;
1057  }
1058
1059  if (!is_pinching) {
1060    // When not pinching, match the ideal page scale factor.
1061    if (raster_page_scale_ != ideal_page_scale_)
1062      return true;
1063  }
1064
1065  // Always match the ideal device scale factor.
1066  if (raster_device_scale_ != ideal_device_scale_)
1067    return true;
1068
1069  // When the source scale changes we want to match it, but not when animating
1070  // or when we've fixed the scale in place.
1071  if (!draw_properties().screen_space_transform_is_animating &&
1072      !raster_source_scale_is_fixed_ &&
1073      raster_source_scale_ != ideal_source_scale_)
1074    return true;
1075
1076  return false;
1077}
1078
1079float PictureLayerImpl::SnappedContentsScale(float scale) {
1080  // If a tiling exists within the max snapping ratio, snap to its scale.
1081  float snapped_contents_scale = scale;
1082  float snapped_ratio = kSnapToExistingTilingRatio;
1083  for (size_t i = 0; i < tilings_->num_tilings(); ++i) {
1084    float tiling_contents_scale = tilings_->tiling_at(i)->contents_scale();
1085    float ratio = PositiveRatio(tiling_contents_scale, scale);
1086    if (ratio < snapped_ratio) {
1087      snapped_contents_scale = tiling_contents_scale;
1088      snapped_ratio = ratio;
1089    }
1090  }
1091  return snapped_contents_scale;
1092}
1093
1094void PictureLayerImpl::RecalculateRasterScales() {
1095  float old_raster_contents_scale = raster_contents_scale_;
1096  float old_raster_page_scale = raster_page_scale_;
1097  float old_raster_source_scale = raster_source_scale_;
1098
1099  raster_device_scale_ = ideal_device_scale_;
1100  raster_page_scale_ = ideal_page_scale_;
1101  raster_source_scale_ = ideal_source_scale_;
1102  raster_contents_scale_ = ideal_contents_scale_;
1103
1104  // If we're not animating, or leaving an animation, and the
1105  // ideal_source_scale_ changes, then things are unpredictable, and we fix
1106  // the raster_source_scale_ in place.
1107  if (old_raster_source_scale &&
1108      !draw_properties().screen_space_transform_is_animating &&
1109      !was_screen_space_transform_animating_ &&
1110      old_raster_source_scale != ideal_source_scale_)
1111    raster_source_scale_is_fixed_ = true;
1112
1113  // TODO(danakj): Adjust raster source scale closer to ideal source scale at
1114  // a throttled rate. Possibly make use of invalidation_.IsEmpty() on pending
1115  // tree. This will allow CSS scale changes to get re-rastered at an
1116  // appropriate rate.
1117  if (raster_source_scale_is_fixed_) {
1118    raster_contents_scale_ /= raster_source_scale_;
1119    raster_source_scale_ = 1.f;
1120  }
1121
1122  // During pinch we completely ignore the current ideal scale, and just use
1123  // a multiple of the previous scale.
1124  // TODO(danakj): This seems crazy, we should use the current ideal, no?
1125  bool is_pinching = layer_tree_impl()->PinchGestureActive();
1126  if (is_pinching && old_raster_contents_scale) {
1127    // See ShouldAdjustRasterScale:
1128    // - When zooming out, preemptively create new tiling at lower resolution.
1129    // - When zooming in, approximate ideal using multiple of kMaxScaleRatio.
1130    bool zooming_out = old_raster_page_scale > ideal_page_scale_;
1131    float desired_contents_scale =
1132        zooming_out ? old_raster_contents_scale / kMaxScaleRatioDuringPinch
1133                    : old_raster_contents_scale * kMaxScaleRatioDuringPinch;
1134    raster_contents_scale_ = SnappedContentsScale(desired_contents_scale);
1135    raster_page_scale_ =
1136        raster_contents_scale_ / raster_device_scale_ / raster_source_scale_;
1137  }
1138
1139  raster_contents_scale_ =
1140      std::max(raster_contents_scale_, MinimumContentsScale());
1141
1142  // Since we're not re-rasterizing during animation, rasterize at the maximum
1143  // scale that will occur during the animation, if the maximum scale is
1144  // known. However, to avoid excessive memory use, don't rasterize at a scale
1145  // at which this layer would become larger than the viewport.
1146  if (draw_properties().screen_space_transform_is_animating) {
1147    bool can_raster_at_maximum_scale = false;
1148    if (draw_properties().maximum_animation_contents_scale > 0.f) {
1149      gfx::Size bounds_at_maximum_scale = gfx::ToCeiledSize(gfx::ScaleSize(
1150          bounds(), draw_properties().maximum_animation_contents_scale));
1151      if (bounds_at_maximum_scale.GetArea() <=
1152          layer_tree_impl()->device_viewport_size().GetArea())
1153        can_raster_at_maximum_scale = true;
1154    }
1155    if (can_raster_at_maximum_scale) {
1156      raster_contents_scale_ =
1157          std::max(raster_contents_scale_,
1158                   draw_properties().maximum_animation_contents_scale);
1159    } else {
1160      raster_contents_scale_ =
1161          std::max(raster_contents_scale_,
1162                   1.f * ideal_page_scale_ * ideal_device_scale_);
1163    }
1164  }
1165
1166  // If this layer would only create one tile at this content scale,
1167  // don't create a low res tiling.
1168  gfx::Size content_bounds =
1169      gfx::ToCeiledSize(gfx::ScaleSize(bounds(), raster_contents_scale_));
1170  gfx::Size tile_size = CalculateTileSize(content_bounds);
1171  if (tile_size.width() >= content_bounds.width() &&
1172      tile_size.height() >= content_bounds.height()) {
1173    low_res_raster_contents_scale_ = raster_contents_scale_;
1174    return;
1175  }
1176
1177  float low_res_factor =
1178      layer_tree_impl()->settings().low_res_contents_scale_factor;
1179  low_res_raster_contents_scale_ = std::max(
1180      raster_contents_scale_ * low_res_factor,
1181      MinimumContentsScale());
1182}
1183
1184void PictureLayerImpl::CleanUpTilingsOnActiveLayer(
1185    std::vector<PictureLayerTiling*> used_tilings) {
1186  DCHECK(layer_tree_impl()->IsActiveTree());
1187  if (tilings_->num_tilings() == 0)
1188    return;
1189
1190  float min_acceptable_high_res_scale = std::min(
1191      raster_contents_scale_, ideal_contents_scale_);
1192  float max_acceptable_high_res_scale = std::max(
1193      raster_contents_scale_, ideal_contents_scale_);
1194  float twin_low_res_scale = 0.f;
1195
1196  PictureLayerImpl* twin = twin_layer_;
1197  if (twin && twin->CanHaveTilings()) {
1198    min_acceptable_high_res_scale = std::min(
1199        min_acceptable_high_res_scale,
1200        std::min(twin->raster_contents_scale_, twin->ideal_contents_scale_));
1201    max_acceptable_high_res_scale = std::max(
1202        max_acceptable_high_res_scale,
1203        std::max(twin->raster_contents_scale_, twin->ideal_contents_scale_));
1204
1205    for (size_t i = 0; i < twin->tilings_->num_tilings(); ++i) {
1206      PictureLayerTiling* tiling = twin->tilings_->tiling_at(i);
1207      if (tiling->resolution() == LOW_RESOLUTION)
1208        twin_low_res_scale = tiling->contents_scale();
1209    }
1210  }
1211
1212  std::vector<PictureLayerTiling*> to_remove;
1213  for (size_t i = 0; i < tilings_->num_tilings(); ++i) {
1214    PictureLayerTiling* tiling = tilings_->tiling_at(i);
1215
1216    // Keep multiple high resolution tilings even if not used to help
1217    // activate earlier at non-ideal resolutions.
1218    if (tiling->contents_scale() >= min_acceptable_high_res_scale &&
1219        tiling->contents_scale() <= max_acceptable_high_res_scale)
1220      continue;
1221
1222    // Keep low resolution tilings, if the layer should have them.
1223    if (layer_tree_impl()->create_low_res_tiling()) {
1224      if (tiling->resolution() == LOW_RESOLUTION ||
1225          tiling->contents_scale() == twin_low_res_scale)
1226        continue;
1227    }
1228
1229    // Don't remove tilings that are being used (and thus would cause a flash.)
1230    if (std::find(used_tilings.begin(), used_tilings.end(), tiling) !=
1231        used_tilings.end())
1232      continue;
1233
1234    to_remove.push_back(tiling);
1235  }
1236
1237  if (to_remove.empty())
1238    return;
1239
1240  PictureLayerImpl* recycled_twin = GetRecycledTwinLayer();
1241  // Remove tilings on this tree and the twin tree.
1242  for (size_t i = 0; i < to_remove.size(); ++i) {
1243    const PictureLayerTiling* twin_tiling = GetTwinTiling(to_remove[i]);
1244    // Only remove tilings from the twin layer if they have
1245    // NON_IDEAL_RESOLUTION.
1246    if (twin_tiling && twin_tiling->resolution() == NON_IDEAL_RESOLUTION)
1247      twin->RemoveTiling(to_remove[i]->contents_scale());
1248    // Remove the tiling from the recycle tree. Note that we ignore resolution,
1249    // since we don't need to maintain high/low res on the recycle tree.
1250    if (recycled_twin)
1251      recycled_twin->RemoveTiling(to_remove[i]->contents_scale());
1252    // TODO(enne): temporary sanity CHECK for http://crbug.com/358350
1253    CHECK_NE(HIGH_RESOLUTION, to_remove[i]->resolution());
1254    tilings_->Remove(to_remove[i]);
1255  }
1256
1257  DCHECK_GT(tilings_->num_tilings(), 0u);
1258  SanityCheckTilingState();
1259}
1260
1261float PictureLayerImpl::MinimumContentsScale() const {
1262  float setting_min = layer_tree_impl()->settings().minimum_contents_scale;
1263
1264  // If the contents scale is less than 1 / width (also for height),
1265  // then it will end up having less than one pixel of content in that
1266  // dimension.  Bump the minimum contents scale up in this case to prevent
1267  // this from happening.
1268  int min_dimension = std::min(bounds().width(), bounds().height());
1269  if (!min_dimension)
1270    return setting_min;
1271
1272  return std::max(1.f / min_dimension, setting_min);
1273}
1274
1275void PictureLayerImpl::ResetRasterScale() {
1276  raster_page_scale_ = 0.f;
1277  raster_device_scale_ = 0.f;
1278  raster_source_scale_ = 0.f;
1279  raster_contents_scale_ = 0.f;
1280  low_res_raster_contents_scale_ = 0.f;
1281  raster_source_scale_is_fixed_ = false;
1282
1283  // When raster scales aren't valid, don't update tile priorities until
1284  // this layer has been updated via UpdateDrawProperties.
1285  should_update_tile_priorities_ = false;
1286}
1287
1288bool PictureLayerImpl::CanHaveTilings() const {
1289  if (!DrawsContent())
1290    return false;
1291  if (!pile_->HasRecordings())
1292    return false;
1293  return true;
1294}
1295
1296bool PictureLayerImpl::CanHaveTilingWithScale(float contents_scale) const {
1297  if (!CanHaveTilings())
1298    return false;
1299  if (contents_scale < MinimumContentsScale())
1300    return false;
1301  return true;
1302}
1303
1304void PictureLayerImpl::SanityCheckTilingState() const {
1305#if DCHECK_IS_ON
1306  // Recycle tree doesn't have any restrictions.
1307  if (layer_tree_impl()->IsRecycleTree())
1308    return;
1309
1310  if (!CanHaveTilings()) {
1311    DCHECK_EQ(0u, tilings_->num_tilings());
1312    return;
1313  }
1314  if (tilings_->num_tilings() == 0)
1315    return;
1316
1317  // MarkVisibleResourcesAsRequired depends on having exactly 1 high res
1318  // tiling to mark its tiles as being required for activation.
1319  DCHECK_EQ(1, tilings_->NumHighResTilings());
1320#endif
1321}
1322
1323float PictureLayerImpl::MaximumTilingContentsScale() const {
1324  float max_contents_scale = MinimumContentsScale();
1325  for (size_t i = 0; i < tilings_->num_tilings(); ++i) {
1326    const PictureLayerTiling* tiling = tilings_->tiling_at(i);
1327    max_contents_scale = std::max(max_contents_scale, tiling->contents_scale());
1328  }
1329  return max_contents_scale;
1330}
1331
1332void PictureLayerImpl::UpdateIdealScales() {
1333  DCHECK(CanHaveTilings());
1334
1335  float min_contents_scale = MinimumContentsScale();
1336  DCHECK_GT(min_contents_scale, 0.f);
1337  float min_page_scale = layer_tree_impl()->min_page_scale_factor();
1338  DCHECK_GT(min_page_scale, 0.f);
1339  float min_device_scale = 1.f;
1340  float min_source_scale =
1341      min_contents_scale / min_page_scale / min_device_scale;
1342
1343  float ideal_page_scale = draw_properties().page_scale_factor;
1344  float ideal_device_scale = draw_properties().device_scale_factor;
1345  float ideal_source_scale = draw_properties().ideal_contents_scale /
1346                             ideal_page_scale / ideal_device_scale;
1347  ideal_contents_scale_ =
1348      std::max(draw_properties().ideal_contents_scale, min_contents_scale);
1349  ideal_page_scale_ = draw_properties().page_scale_factor;
1350  ideal_device_scale_ = draw_properties().device_scale_factor;
1351  ideal_source_scale_ = std::max(ideal_source_scale, min_source_scale);
1352}
1353
1354void PictureLayerImpl::GetDebugBorderProperties(
1355    SkColor* color,
1356    float* width) const {
1357  *color = DebugColors::TiledContentLayerBorderColor();
1358  *width = DebugColors::TiledContentLayerBorderWidth(layer_tree_impl());
1359}
1360
1361void PictureLayerImpl::GetAllTilesForTracing(
1362    std::set<const Tile*>* tiles) const {
1363  if (!tilings_)
1364    return;
1365
1366  for (size_t i = 0; i < tilings_->num_tilings(); ++i)
1367    tilings_->tiling_at(i)->GetAllTilesForTracing(tiles);
1368}
1369
1370void PictureLayerImpl::AsValueInto(base::DictionaryValue* state) const {
1371  const_cast<PictureLayerImpl*>(this)->DoPostCommitInitializationIfNeeded();
1372  LayerImpl::AsValueInto(state);
1373  state->SetDouble("ideal_contents_scale", ideal_contents_scale_);
1374  state->SetDouble("geometry_contents_scale", MaximumTilingContentsScale());
1375  state->Set("tilings", tilings_->AsValue().release());
1376  state->Set("pictures", pile_->AsValue().release());
1377  state->Set("invalidation", invalidation_.AsValue().release());
1378
1379  scoped_ptr<base::ListValue> coverage_tiles(new base::ListValue);
1380  for (PictureLayerTilingSet::CoverageIterator iter(tilings_.get(),
1381                                                    contents_scale_x(),
1382                                                    gfx::Rect(content_bounds()),
1383                                                    ideal_contents_scale_);
1384       iter;
1385       ++iter) {
1386    scoped_ptr<base::DictionaryValue> tile_data(new base::DictionaryValue);
1387    tile_data->Set("geometry_rect",
1388                   MathUtil::AsValue(iter.geometry_rect()).release());
1389    if (*iter)
1390      tile_data->Set("tile", TracedValue::CreateIDRef(*iter).release());
1391
1392    coverage_tiles->Append(tile_data.release());
1393  }
1394  state->Set("coverage_tiles", coverage_tiles.release());
1395}
1396
1397size_t PictureLayerImpl::GPUMemoryUsageInBytes() const {
1398  const_cast<PictureLayerImpl*>(this)->DoPostCommitInitializationIfNeeded();
1399  return tilings_->GPUMemoryUsageInBytes();
1400}
1401
1402void PictureLayerImpl::RunMicroBenchmark(MicroBenchmarkImpl* benchmark) {
1403  benchmark->RunOnLayer(this);
1404}
1405
1406WhichTree PictureLayerImpl::GetTree() const {
1407  return layer_tree_impl()->IsActiveTree() ? ACTIVE_TREE : PENDING_TREE;
1408}
1409
1410bool PictureLayerImpl::IsOnActiveOrPendingTree() const {
1411  return !layer_tree_impl()->IsRecycleTree();
1412}
1413
1414bool PictureLayerImpl::HasValidTilePriorities() const {
1415  return IsOnActiveOrPendingTree() && IsDrawnRenderSurfaceLayerListMember();
1416}
1417
1418bool PictureLayerImpl::AllTilesRequiredForActivationAreReadyToDraw() const {
1419  if (!layer_tree_impl()->IsPendingTree())
1420    return true;
1421
1422  if (!HasValidTilePriorities())
1423    return true;
1424
1425  if (!tilings_)
1426    return true;
1427
1428  if (visible_rect_for_tile_priority_.IsEmpty())
1429    return true;
1430
1431  for (size_t i = 0; i < tilings_->num_tilings(); ++i) {
1432    PictureLayerTiling* tiling = tilings_->tiling_at(i);
1433    if (tiling->resolution() != HIGH_RESOLUTION &&
1434        tiling->resolution() != LOW_RESOLUTION)
1435      continue;
1436
1437    gfx::Rect rect(visible_rect_for_tile_priority_);
1438    for (PictureLayerTiling::CoverageIterator iter(
1439             tiling, contents_scale_x(), rect);
1440         iter;
1441         ++iter) {
1442      const Tile* tile = *iter;
1443      // A null tile (i.e. missing recording) can just be skipped.
1444      if (!tile)
1445        continue;
1446
1447      if (tile->required_for_activation() && !tile->IsReadyToDraw())
1448        return false;
1449    }
1450  }
1451
1452  return true;
1453}
1454
1455PictureLayerImpl::LayerRasterTileIterator::LayerRasterTileIterator()
1456    : layer_(NULL) {}
1457
1458PictureLayerImpl::LayerRasterTileIterator::LayerRasterTileIterator(
1459    PictureLayerImpl* layer,
1460    bool prioritize_low_res)
1461    : layer_(layer), current_stage_(0) {
1462  DCHECK(layer_);
1463
1464  // Early out if the layer has no tilings.
1465  if (!layer_->tilings_ || !layer_->tilings_->num_tilings()) {
1466    current_stage_ = arraysize(stages_);
1467    return;
1468  }
1469
1470  // Tiles without valid priority are treated as having lowest priority and
1471  // never considered for raster.
1472  if (!layer_->HasValidTilePriorities()) {
1473    current_stage_ = arraysize(stages_);
1474    return;
1475  }
1476
1477  WhichTree tree =
1478      layer_->layer_tree_impl()->IsActiveTree() ? ACTIVE_TREE : PENDING_TREE;
1479
1480  // Find high and low res tilings and initialize the iterators.
1481  for (size_t i = 0; i < layer_->tilings_->num_tilings(); ++i) {
1482    PictureLayerTiling* tiling = layer_->tilings_->tiling_at(i);
1483    if (tiling->resolution() == HIGH_RESOLUTION) {
1484      iterators_[HIGH_RES] =
1485          PictureLayerTiling::TilingRasterTileIterator(tiling, tree);
1486    }
1487
1488    if (tiling->resolution() == LOW_RESOLUTION) {
1489      iterators_[LOW_RES] =
1490          PictureLayerTiling::TilingRasterTileIterator(tiling, tree);
1491    }
1492  }
1493
1494  if (prioritize_low_res) {
1495    stages_[0].iterator_type = LOW_RES;
1496    stages_[0].tile_type = TilePriority::NOW;
1497
1498    stages_[1].iterator_type = HIGH_RES;
1499    stages_[1].tile_type = TilePriority::NOW;
1500  } else {
1501    stages_[0].iterator_type = HIGH_RES;
1502    stages_[0].tile_type = TilePriority::NOW;
1503
1504    stages_[1].iterator_type = LOW_RES;
1505    stages_[1].tile_type = TilePriority::NOW;
1506  }
1507
1508  stages_[2].iterator_type = HIGH_RES;
1509  stages_[2].tile_type = TilePriority::SOON;
1510
1511  stages_[3].iterator_type = HIGH_RES;
1512  stages_[3].tile_type = TilePriority::EVENTUALLY;
1513
1514  IteratorType index = stages_[current_stage_].iterator_type;
1515  TilePriority::PriorityBin tile_type = stages_[current_stage_].tile_type;
1516  if (!iterators_[index] || iterators_[index].get_type() != tile_type)
1517    ++(*this);
1518}
1519
1520PictureLayerImpl::LayerRasterTileIterator::~LayerRasterTileIterator() {}
1521
1522PictureLayerImpl::LayerRasterTileIterator::operator bool() const {
1523  return layer_ && static_cast<size_t>(current_stage_) < arraysize(stages_);
1524}
1525
1526PictureLayerImpl::LayerRasterTileIterator&
1527PictureLayerImpl::LayerRasterTileIterator::
1528operator++() {
1529  IteratorType index = stages_[current_stage_].iterator_type;
1530  TilePriority::PriorityBin tile_type = stages_[current_stage_].tile_type;
1531
1532  // First advance the iterator.
1533  if (iterators_[index])
1534    ++iterators_[index];
1535
1536  if (iterators_[index] && iterators_[index].get_type() == tile_type)
1537    return *this;
1538
1539  // Next, advance the stage.
1540  int stage_count = arraysize(stages_);
1541  ++current_stage_;
1542  while (current_stage_ < stage_count) {
1543    index = stages_[current_stage_].iterator_type;
1544    tile_type = stages_[current_stage_].tile_type;
1545
1546    if (iterators_[index] && iterators_[index].get_type() == tile_type)
1547      break;
1548    ++current_stage_;
1549  }
1550  return *this;
1551}
1552
1553Tile* PictureLayerImpl::LayerRasterTileIterator::operator*() {
1554  DCHECK(*this);
1555
1556  IteratorType index = stages_[current_stage_].iterator_type;
1557  DCHECK(iterators_[index]);
1558  DCHECK(iterators_[index].get_type() == stages_[current_stage_].tile_type);
1559
1560  return *iterators_[index];
1561}
1562
1563PictureLayerImpl::LayerEvictionTileIterator::LayerEvictionTileIterator()
1564    : iterator_index_(0),
1565      iteration_stage_(TilePriority::EVENTUALLY),
1566      required_for_activation_(false),
1567      layer_(NULL) {}
1568
1569PictureLayerImpl::LayerEvictionTileIterator::LayerEvictionTileIterator(
1570    PictureLayerImpl* layer,
1571    TreePriority tree_priority)
1572    : iterator_index_(0),
1573      iteration_stage_(TilePriority::EVENTUALLY),
1574      required_for_activation_(false),
1575      layer_(layer) {
1576  // Early out if the layer has no tilings.
1577  // TODO(vmpstr): Once tile priorities are determined by the iterators, ensure
1578  // that layers that don't have valid tile priorities have lowest priorities so
1579  // they evict their tiles first (crbug.com/381704)
1580  if (!layer_->tilings_ || !layer_->tilings_->num_tilings())
1581    return;
1582
1583  size_t high_res_tiling_index = layer_->tilings_->num_tilings();
1584  size_t low_res_tiling_index = layer_->tilings_->num_tilings();
1585  for (size_t i = 0; i < layer_->tilings_->num_tilings(); ++i) {
1586    PictureLayerTiling* tiling = layer_->tilings_->tiling_at(i);
1587    if (tiling->resolution() == HIGH_RESOLUTION)
1588      high_res_tiling_index = i;
1589    else if (tiling->resolution() == LOW_RESOLUTION)
1590      low_res_tiling_index = i;
1591  }
1592
1593  iterators_.reserve(layer_->tilings_->num_tilings());
1594
1595  // Higher resolution non-ideal goes first.
1596  for (size_t i = 0; i < high_res_tiling_index; ++i) {
1597    iterators_.push_back(PictureLayerTiling::TilingEvictionTileIterator(
1598        layer_->tilings_->tiling_at(i), tree_priority));
1599  }
1600
1601  // Lower resolution non-ideal goes next.
1602  for (size_t i = layer_->tilings_->num_tilings() - 1;
1603       i > high_res_tiling_index;
1604       --i) {
1605    PictureLayerTiling* tiling = layer_->tilings_->tiling_at(i);
1606    if (tiling->resolution() == LOW_RESOLUTION)
1607      continue;
1608
1609    iterators_.push_back(
1610        PictureLayerTiling::TilingEvictionTileIterator(tiling, tree_priority));
1611  }
1612
1613  // Now, put the low res tiling if we have one.
1614  if (low_res_tiling_index < layer_->tilings_->num_tilings()) {
1615    iterators_.push_back(PictureLayerTiling::TilingEvictionTileIterator(
1616        layer_->tilings_->tiling_at(low_res_tiling_index), tree_priority));
1617  }
1618
1619  // Finally, put the high res tiling if we have one.
1620  if (high_res_tiling_index < layer_->tilings_->num_tilings()) {
1621    iterators_.push_back(PictureLayerTiling::TilingEvictionTileIterator(
1622        layer_->tilings_->tiling_at(high_res_tiling_index), tree_priority));
1623  }
1624
1625  DCHECK_GT(iterators_.size(), 0u);
1626
1627  if (!iterators_[iterator_index_] ||
1628      !IsCorrectType(&iterators_[iterator_index_])) {
1629    AdvanceToNextIterator();
1630  }
1631}
1632
1633PictureLayerImpl::LayerEvictionTileIterator::~LayerEvictionTileIterator() {}
1634
1635Tile* PictureLayerImpl::LayerEvictionTileIterator::operator*() {
1636  DCHECK(*this);
1637  return *iterators_[iterator_index_];
1638}
1639
1640PictureLayerImpl::LayerEvictionTileIterator&
1641PictureLayerImpl::LayerEvictionTileIterator::
1642operator++() {
1643  DCHECK(*this);
1644  ++iterators_[iterator_index_];
1645  if (!iterators_[iterator_index_] ||
1646      !IsCorrectType(&iterators_[iterator_index_])) {
1647    AdvanceToNextIterator();
1648  }
1649  return *this;
1650}
1651
1652void PictureLayerImpl::LayerEvictionTileIterator::AdvanceToNextIterator() {
1653  ++iterator_index_;
1654
1655  while (true) {
1656    while (iterator_index_ < iterators_.size()) {
1657      if (iterators_[iterator_index_] &&
1658          IsCorrectType(&iterators_[iterator_index_])) {
1659        return;
1660      }
1661      ++iterator_index_;
1662    }
1663
1664    // If we're NOW and required_for_activation, then this was the last pass
1665    // through the iterators.
1666    if (iteration_stage_ == TilePriority::NOW && required_for_activation_)
1667      break;
1668
1669    if (!required_for_activation_) {
1670      required_for_activation_ = true;
1671    } else {
1672      required_for_activation_ = false;
1673      iteration_stage_ =
1674          static_cast<TilePriority::PriorityBin>(iteration_stage_ - 1);
1675    }
1676    iterator_index_ = 0;
1677  }
1678}
1679
1680PictureLayerImpl::LayerEvictionTileIterator::operator bool() const {
1681  return iterator_index_ < iterators_.size();
1682}
1683
1684bool PictureLayerImpl::LayerEvictionTileIterator::IsCorrectType(
1685    PictureLayerTiling::TilingEvictionTileIterator* it) const {
1686  return it->get_type() == iteration_stage_ &&
1687         (**it)->required_for_activation() == required_for_activation_;
1688}
1689
1690}  // namespace cc
1691