autocomplete_controller.cc revision ca12bfac764ba476d6cd062bf1dde12cc64c3f40 
1// Copyright (c) 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 "chrome/browser/autocomplete/autocomplete_controller.h"
6
7#include <set>
8#include <string>
9
10#include "base/command_line.h"
11#include "base/format_macros.h"
12#include "base/logging.h"
13#include "base/metrics/histogram.h"
14#include "base/strings/string_number_conversions.h"
15#include "base/strings/stringprintf.h"
16#include "base/time/time.h"
17#include "chrome/browser/autocomplete/autocomplete_controller_delegate.h"
18#include "chrome/browser/autocomplete/bookmark_provider.h"
19#include "chrome/browser/autocomplete/builtin_provider.h"
20#include "chrome/browser/autocomplete/extension_app_provider.h"
21#include "chrome/browser/autocomplete/history_quick_provider.h"
22#include "chrome/browser/autocomplete/history_url_provider.h"
23#include "chrome/browser/autocomplete/keyword_provider.h"
24#include "chrome/browser/autocomplete/search_provider.h"
25#include "chrome/browser/autocomplete/shortcuts_provider.h"
26#include "chrome/browser/autocomplete/zero_suggest_provider.h"
27#include "chrome/browser/chrome_notification_types.h"
28#include "chrome/browser/omnibox/omnibox_field_trial.h"
29#include "chrome/browser/profiles/profile.h"
30#include "chrome/browser/search/search.h"
31#include "chrome/browser/search_engines/template_url.h"
32#include "chrome/common/chrome_switches.h"
33#include "content/public/browser/notification_service.h"
34#include "grit/generated_resources.h"
35#include "grit/theme_resources.h"
36#include "ui/base/l10n/l10n_util.h"
37
38#if defined(OS_CHROMEOS)
39#include "chrome/browser/autocomplete/contact_provider_chromeos.h"
40#include "chrome/browser/chromeos/contacts/contact_manager.h"
41#endif
42
43namespace {
44
45// Converts the given match to a type (and possibly subtype) based on the AQS
46// specification. For more details, see
47// http://goto.google.com/binary-clients-logging.
48void AutocompleteMatchToAssistedQuery(
49    const AutocompleteMatch::Type& match, size_t* type, size_t* subtype) {
50  // This type indicates a native chrome suggestion.
51  *type = 69;
52  // Default value, indicating no subtype.
53  *subtype = string16::npos;
54
55  switch (match) {
56    case AutocompleteMatchType::SEARCH_SUGGEST: {
57      *type = 0;
58      return;
59    }
60    case AutocompleteMatchType::NAVSUGGEST: {
61      *type = 5;
62      return;
63    }
64    case AutocompleteMatchType::SEARCH_WHAT_YOU_TYPED: {
65      *subtype = 57;
66      return;
67    }
68    case AutocompleteMatchType::URL_WHAT_YOU_TYPED: {
69      *subtype = 58;
70      return;
71    }
72    case AutocompleteMatchType::SEARCH_HISTORY: {
73      *subtype = 59;
74      return;
75    }
76    case AutocompleteMatchType::HISTORY_URL: {
77      *subtype = 60;
78      return;
79    }
80    case AutocompleteMatchType::HISTORY_TITLE: {
81      *subtype = 61;
82      return;
83    }
84    case AutocompleteMatchType::HISTORY_BODY: {
85      *subtype = 62;
86      return;
87    }
88    case AutocompleteMatchType::HISTORY_KEYWORD: {
89      *subtype = 63;
90      return;
91    }
92    case AutocompleteMatchType::BOOKMARK_TITLE: {
93      *subtype = 65;
94      return;
95    }
96    default: {
97      // This value indicates a native chrome suggestion with no named subtype
98      // (yet).
99      *subtype = 64;
100    }
101  }
102}
103
104// Appends available autocompletion of the given type, subtype, and number to
105// the existing available autocompletions string, encoding according to the
106// spec.
107void AppendAvailableAutocompletion(size_t type,
108                                   size_t subtype,
109                                   int count,
110                                   std::string* autocompletions) {
111  if (!autocompletions->empty())
112    autocompletions->append("j");
113  base::StringAppendF(autocompletions, "%" PRIuS, type);
114  // Subtype is optional - string16::npos indicates no subtype.
115  if (subtype != string16::npos)
116    base::StringAppendF(autocompletions, "i%" PRIuS, subtype);
117  if (count > 1)
118    base::StringAppendF(autocompletions, "l%d", count);
119}
120
121// Returns whether the autocompletion is trivial enough that we consider it
122// an autocompletion for which the omnibox autocompletion code did not add
123// any value.
124bool IsTrivialAutocompletion(const AutocompleteMatch& match) {
125  return match.type == AutocompleteMatchType::SEARCH_WHAT_YOU_TYPED ||
126      match.type == AutocompleteMatchType::URL_WHAT_YOU_TYPED ||
127      match.type == AutocompleteMatchType::SEARCH_OTHER_ENGINE;
128}
129
130}  // namespace
131
132const int AutocompleteController::kNoItemSelected = -1;
133
134AutocompleteController::AutocompleteController(
135    Profile* profile,
136    AutocompleteControllerDelegate* delegate,
137    int provider_types)
138    : delegate_(delegate),
139      history_url_provider_(NULL),
140      keyword_provider_(NULL),
141      search_provider_(NULL),
142      zero_suggest_provider_(NULL),
143      in_stop_timer_field_trial_(
144          OmniboxFieldTrial::InStopTimerFieldTrialExperimentGroup()),
145      done_(true),
146      in_start_(false),
147      in_zero_suggest_(false),
148      profile_(profile) {
149  // AND with the disabled providers, if any.
150  provider_types &= ~OmniboxFieldTrial::GetDisabledProviderTypes();
151  bool use_hqp = !!(provider_types & AutocompleteProvider::TYPE_HISTORY_QUICK);
152  // TODO(mrossetti): Permanently modify the HistoryURLProvider to not search
153  // titles once HQP is turned on permanently.
154
155  if (provider_types & AutocompleteProvider::TYPE_BUILTIN)
156    providers_.push_back(new BuiltinProvider(this, profile));
157#if defined(OS_CHROMEOS)
158  if (provider_types & AutocompleteProvider::TYPE_CONTACT)
159    providers_.push_back(new ContactProvider(this, profile,
160        contacts::ContactManager::GetInstance()->GetWeakPtr()));
161#endif
162  if (provider_types & AutocompleteProvider::TYPE_EXTENSION_APP)
163    providers_.push_back(new ExtensionAppProvider(this, profile));
164  if (use_hqp)
165    providers_.push_back(new HistoryQuickProvider(this, profile));
166  if (provider_types & AutocompleteProvider::TYPE_HISTORY_URL) {
167    history_url_provider_ = new HistoryURLProvider(this, profile);
168    providers_.push_back(history_url_provider_);
169  }
170  // Search provider/"tab to search" can be used on all platforms other than
171  // Android.
172#if !defined(OS_ANDROID)
173  if (provider_types & AutocompleteProvider::TYPE_KEYWORD) {
174    keyword_provider_ = new KeywordProvider(this, profile);
175    providers_.push_back(keyword_provider_);
176  }
177#endif
178  if (provider_types & AutocompleteProvider::TYPE_SEARCH) {
179    search_provider_ = new SearchProvider(this, profile);
180    providers_.push_back(search_provider_);
181  }
182  if (provider_types & AutocompleteProvider::TYPE_SHORTCUTS)
183    providers_.push_back(new ShortcutsProvider(this, profile));
184
185  // Create ZeroSuggest if it is enabled.
186  if (provider_types & AutocompleteProvider::TYPE_ZERO_SUGGEST) {
187    zero_suggest_provider_ = ZeroSuggestProvider::Create(this, profile);
188    if (zero_suggest_provider_)
189      providers_.push_back(zero_suggest_provider_);
190  }
191
192  if ((provider_types & AutocompleteProvider::TYPE_BOOKMARK) &&
193      !CommandLine::ForCurrentProcess()->HasSwitch(
194          switches::kDisableBookmarkAutocompleteProvider))
195    providers_.push_back(new BookmarkProvider(this, profile));
196
197  for (ACProviders::iterator i(providers_.begin()); i != providers_.end(); ++i)
198    (*i)->AddRef();
199}
200
201AutocompleteController::~AutocompleteController() {
202  // The providers may have tasks outstanding that hold refs to them.  We need
203  // to ensure they won't call us back if they outlive us.  (Practically,
204  // calling Stop() should also cancel those tasks and make it so that we hold
205  // the only refs.)  We also don't want to bother notifying anyone of our
206  // result changes here, because the notification observer is in the midst of
207  // shutdown too, so we don't ask Stop() to clear |result_| (and notify).
208  result_.Reset();  // Not really necessary.
209  Stop(false);
210
211  for (ACProviders::iterator i(providers_.begin()); i != providers_.end(); ++i)
212    (*i)->Release();
213
214  providers_.clear();  // Not really necessary.
215}
216
217void AutocompleteController::Start(const AutocompleteInput& input) {
218  const string16 old_input_text(input_.text());
219  const AutocompleteInput::MatchesRequested old_matches_requested =
220      input_.matches_requested();
221  input_ = input;
222
223  // See if we can avoid rerunning autocomplete when the query hasn't changed
224  // much.  When the user presses or releases the ctrl key, the desired_tld
225  // changes, and when the user finishes an IME composition, inline autocomplete
226  // may no longer be prevented.  In both these cases the text itself hasn't
227  // changed since the last query, and some providers can do much less work (and
228  // get matches back more quickly).  Taking advantage of this reduces flicker.
229  //
230  // NOTE: This comes after constructing |input_| above since that construction
231  // can change the text string (e.g. by stripping off a leading '?').
232  const bool minimal_changes = (input_.text() == old_input_text) &&
233      (input_.matches_requested() == old_matches_requested);
234
235  expire_timer_.Stop();
236  stop_timer_.Stop();
237
238  // Start the new query.
239  in_zero_suggest_ = false;
240  in_start_ = true;
241  base::TimeTicks start_time = base::TimeTicks::Now();
242  for (ACProviders::iterator i(providers_.begin()); i != providers_.end();
243       ++i) {
244    // TODO(mpearson): Remove timing code once bugs 178705 / 237703 / 168933
245    // are resolved.
246    base::TimeTicks provider_start_time = base::TimeTicks::Now();
247    (*i)->Start(input_, minimal_changes);
248    if (input.matches_requested() != AutocompleteInput::ALL_MATCHES)
249      DCHECK((*i)->done());
250    base::TimeTicks provider_end_time = base::TimeTicks::Now();
251    std::string name = std::string("Omnibox.ProviderTime.") + (*i)->GetName();
252    base::HistogramBase* counter = base::Histogram::FactoryGet(
253        name, 1, 5000, 20, base::Histogram::kUmaTargetedHistogramFlag);
254    counter->Add(static_cast<int>(
255        (provider_end_time - provider_start_time).InMilliseconds()));
256  }
257  if (input.matches_requested() == AutocompleteInput::ALL_MATCHES &&
258      (input.text().length() < 6)) {
259    base::TimeTicks end_time = base::TimeTicks::Now();
260    std::string name = "Omnibox.QueryTime." + base::IntToString(
261        input.text().length());
262    base::HistogramBase* counter = base::Histogram::FactoryGet(
263        name, 1, 1000, 50, base::Histogram::kUmaTargetedHistogramFlag);
264    counter->Add(static_cast<int>((end_time - start_time).InMilliseconds()));
265  }
266  in_start_ = false;
267  CheckIfDone();
268  // The second true forces saying the default match has changed.
269  // This triggers the edit model to update things such as the inline
270  // autocomplete state.  In particular, if the user has typed a key
271  // since the last notification, and we're now re-running
272  // autocomplete, then we need to update the inline autocompletion
273  // even if the current match is for the same URL as the last run's
274  // default match.  Likewise, the controller doesn't know what's
275  // happened in the edit since the last time it ran autocomplete.
276  // The user might have selected all the text and hit delete, then
277  // typed a new character.  The selection and delete won't send any
278  // signals to the controller so it doesn't realize that anything was
279  // cleared or changed.  Even if the default match hasn't changed, we
280  // need the edit model to update the display.
281  UpdateResult(false, true);
282
283  if (!done_) {
284    StartExpireTimer();
285    StartStopTimer();
286  }
287}
288
289void AutocompleteController::Stop(bool clear_result) {
290  for (ACProviders::const_iterator i(providers_.begin()); i != providers_.end();
291       ++i) {
292    (*i)->Stop(clear_result);
293  }
294
295  expire_timer_.Stop();
296  stop_timer_.Stop();
297  done_ = true;
298  if (clear_result && !result_.empty()) {
299    result_.Reset();
300    // NOTE: We pass in false since we're trying to only clear the popup, not
301    // touch the edit... this is all a mess and should be cleaned up :(
302    NotifyChanged(false);
303  }
304}
305
306void AutocompleteController::StartZeroSuggest(const GURL& url,
307                                              const string16& permanent_text) {
308  if (zero_suggest_provider_ != NULL) {
309    DCHECK(!in_start_);  // We should not be already running a query.
310    in_zero_suggest_ = true;
311    zero_suggest_provider_->StartZeroSuggest(url, permanent_text);
312  }
313}
314
315void AutocompleteController::StopZeroSuggest() {
316  if (zero_suggest_provider_ != NULL) {
317    DCHECK(!in_start_);  // We should not be already running a query.
318    zero_suggest_provider_->Stop(false);
319  }
320}
321
322void AutocompleteController::DeleteMatch(const AutocompleteMatch& match) {
323  DCHECK(match.deletable);
324  match.provider->DeleteMatch(match);  // This may synchronously call back to
325                                       // OnProviderUpdate().
326  // If DeleteMatch resulted in a callback to OnProviderUpdate and we're
327  // not done, we might attempt to redisplay the deleted match. Make sure
328  // we aren't displaying it by removing any old entries.
329  ExpireCopiedEntries();
330}
331
332void AutocompleteController::ExpireCopiedEntries() {
333  // The first true makes UpdateResult() clear out the results and
334  // regenerate them, thus ensuring that no results from the previous
335  // result set remain.
336  UpdateResult(true, false);
337}
338
339void AutocompleteController::OnProviderUpdate(bool updated_matches) {
340  if (in_zero_suggest_) {
341    // We got ZeroSuggest results before Start(). Show only those results,
342    // because results from other providers are stale.
343    result_.Reset();
344    result_.AppendMatches(zero_suggest_provider_->matches());
345    result_.SortAndCull(input_, profile_);
346    NotifyChanged(true);
347  } else {
348    CheckIfDone();
349    // Multiple providers may provide synchronous results, so we only update the
350    // results if we're not in Start().
351    if (!in_start_ && (updated_matches || done_))
352      UpdateResult(false, false);
353  }
354}
355
356void AutocompleteController::AddProvidersInfo(
357    ProvidersInfo* provider_info) const {
358  provider_info->clear();
359  for (ACProviders::const_iterator i(providers_.begin()); i != providers_.end();
360       ++i) {
361    // Add per-provider info, if any.
362    (*i)->AddProviderInfo(provider_info);
363
364    // This is also a good place to put code to add info that you want to
365    // add for every provider.
366  }
367}
368
369void AutocompleteController::ResetSession() {
370  for (ACProviders::const_iterator i(providers_.begin()); i != providers_.end();
371       ++i)
372    (*i)->ResetSession();
373  in_zero_suggest_ = false;
374}
375
376void AutocompleteController::UpdateResult(
377    bool regenerate_result,
378    bool force_notify_default_match_changed) {
379  const bool last_default_was_valid = result_.default_match() != result_.end();
380  // The following three variables are only set and used if
381  // |last_default_was_valid|.
382  string16 last_default_fill_into_edit, last_default_keyword,
383      last_default_associated_keyword;
384  if (last_default_was_valid) {
385    last_default_fill_into_edit = result_.default_match()->fill_into_edit;
386    last_default_keyword = result_.default_match()->keyword;
387    if (result_.default_match()->associated_keyword != NULL)
388      last_default_associated_keyword =
389          result_.default_match()->associated_keyword->keyword;
390  }
391
392  if (regenerate_result)
393    result_.Reset();
394
395  AutocompleteResult last_result;
396  last_result.Swap(&result_);
397
398  for (ACProviders::const_iterator i(providers_.begin()); i != providers_.end();
399       ++i)
400    result_.AppendMatches((*i)->matches());
401
402  // Sort the matches and trim to a small number of "best" matches.
403  result_.SortAndCull(input_, profile_);
404
405  // Need to validate before invoking CopyOldMatches as the old matches are not
406  // valid against the current input.
407#ifndef NDEBUG
408  result_.Validate();
409#endif
410
411  if (!done_) {
412    // This conditional needs to match the conditional in Start that invokes
413    // StartExpireTimer.
414    result_.CopyOldMatches(input_, last_result, profile_);
415  }
416
417  UpdateKeywordDescriptions(&result_);
418  UpdateAssociatedKeywords(&result_);
419  UpdateAssistedQueryStats(&result_);
420
421  const bool default_is_valid = result_.default_match() != result_.end();
422  string16 default_associated_keyword;
423  if (default_is_valid &&
424      (result_.default_match()->associated_keyword != NULL)) {
425    default_associated_keyword =
426        result_.default_match()->associated_keyword->keyword;
427  }
428  // We've gotten async results. Send notification that the default match
429  // updated if fill_into_edit, associated_keyword, or keyword differ.  (The
430  // second can change if we've just started Chrome and the keyword database
431  // finishes loading while processing this request.  The third can change
432  // if we swapped from interpreting the input as a search--which gets
433  // labeled with the default search provider's keyword--to a URL.)
434  // We don't check the URL as that may change for the default match
435  // even though the fill into edit hasn't changed (see SearchProvider
436  // for one case of this).
437  const bool notify_default_match =
438      (last_default_was_valid != default_is_valid) ||
439      (last_default_was_valid &&
440       ((result_.default_match()->fill_into_edit !=
441          last_default_fill_into_edit) ||
442        (default_associated_keyword != last_default_associated_keyword) ||
443        (result_.default_match()->keyword != last_default_keyword)));
444  if (notify_default_match)
445    last_time_default_match_changed_ = base::TimeTicks::Now();
446
447  NotifyChanged(force_notify_default_match_changed || notify_default_match);
448}
449
450void AutocompleteController::UpdateAssociatedKeywords(
451    AutocompleteResult* result) {
452  if (!keyword_provider_)
453    return;
454
455  std::set<string16> keywords;
456  for (ACMatches::iterator match(result->begin()); match != result->end();
457       ++match) {
458    string16 keyword(match->GetSubstitutingExplicitlyInvokedKeyword(profile_));
459    if (!keyword.empty()) {
460      keywords.insert(keyword);
461      continue;
462    }
463
464    // Only add the keyword if the match does not have a duplicate keyword with
465    // a more relevant match.
466    keyword = match->associated_keyword.get() ?
467        match->associated_keyword->keyword :
468        keyword_provider_->GetKeywordForText(match->fill_into_edit);
469    if (!keyword.empty() && !keywords.count(keyword)) {
470      keywords.insert(keyword);
471
472      if (!match->associated_keyword.get())
473        match->associated_keyword.reset(new AutocompleteMatch(
474            keyword_provider_->CreateAutocompleteMatch(match->fill_into_edit,
475                                                       keyword, input_)));
476    } else {
477      match->associated_keyword.reset();
478    }
479  }
480}
481
482void AutocompleteController::UpdateAssistedQueryStats(
483    AutocompleteResult* result) {
484  if (result->empty())
485    return;
486
487  // Build the impressions string (the AQS part after ".").
488  std::string autocompletions;
489  int count = 0;
490  size_t last_type = string16::npos;
491  size_t last_subtype = string16::npos;
492  for (ACMatches::iterator match(result->begin()); match != result->end();
493       ++match) {
494    size_t type = string16::npos;
495    size_t subtype = string16::npos;
496    AutocompleteMatchToAssistedQuery(match->type, &type, &subtype);
497    if (last_type != string16::npos &&
498        (type != last_type || subtype != last_subtype)) {
499      AppendAvailableAutocompletion(
500          last_type, last_subtype, count, &autocompletions);
501      count = 1;
502    } else {
503      count++;
504    }
505    last_type = type;
506    last_subtype = subtype;
507  }
508  AppendAvailableAutocompletion(
509      last_type, last_subtype, count, &autocompletions);
510  // Go over all matches and set AQS if the match supports it.
511  for (size_t index = 0; index < result->size(); ++index) {
512    AutocompleteMatch* match = result->match_at(index);
513    const TemplateURL* template_url = match->GetTemplateURL(profile_, false);
514    if (!template_url || !match->search_terms_args.get())
515      continue;
516    std::string selected_index;
517    // Prevent trivial suggestions from getting credit for being selected.
518    if (!IsTrivialAutocompletion(*match))
519      selected_index = base::StringPrintf("%" PRIuS, index);
520    match->search_terms_args->assisted_query_stats =
521        base::StringPrintf("chrome.%s.%s",
522                           selected_index.c_str(),
523                           autocompletions.c_str());
524    match->destination_url = GURL(template_url->url_ref().ReplaceSearchTerms(
525        *match->search_terms_args));
526  }
527}
528
529GURL AutocompleteController::GetDestinationURL(
530    const AutocompleteMatch& match,
531    base::TimeDelta query_formulation_time) const {
532  GURL destination_url(match.destination_url);
533  TemplateURL* template_url = match.GetTemplateURL(profile_, false);
534
535  // Append the query formulation time (time from when the user first typed a
536  // character into the omnibox to when the user selected a query) and whether
537  // a field trial has triggered to the AQS parameter, if other AQS parameters
538  // were already populated.
539  if (template_url && match.search_terms_args.get() &&
540      !match.search_terms_args->assisted_query_stats.empty()) {
541    TemplateURLRef::SearchTermsArgs search_terms_args(*match.search_terms_args);
542    search_terms_args.assisted_query_stats += base::StringPrintf(
543        ".%" PRId64 "j%d",
544        query_formulation_time.InMilliseconds(),
545        search_provider_ &&
546        search_provider_->field_trial_triggered_in_session());
547    destination_url = GURL(template_url->url_ref().
548                           ReplaceSearchTerms(search_terms_args));
549  }
550  return destination_url;
551}
552
553void AutocompleteController::UpdateKeywordDescriptions(
554    AutocompleteResult* result) {
555  string16 last_keyword;
556  for (AutocompleteResult::iterator i(result->begin()); i != result->end();
557       ++i) {
558    if ((i->provider->type() == AutocompleteProvider::TYPE_KEYWORD &&
559         !i->keyword.empty()) ||
560        (i->provider->type() == AutocompleteProvider::TYPE_SEARCH &&
561         AutocompleteMatch::IsSearchType(i->type))) {
562      i->description.clear();
563      i->description_class.clear();
564      DCHECK(!i->keyword.empty());
565      if (i->keyword != last_keyword) {
566        const TemplateURL* template_url = i->GetTemplateURL(profile_, false);
567        if (template_url) {
568          // For extension keywords, just make the description the extension
569          // name -- don't assume that the normal search keyword description is
570          // applicable.
571          i->description = template_url->AdjustedShortNameForLocaleDirection();
572          if (!template_url->IsExtensionKeyword()) {
573            i->description = l10n_util::GetStringFUTF16(
574                IDS_AUTOCOMPLETE_SEARCH_DESCRIPTION, i->description);
575          }
576          i->description_class.push_back(
577              ACMatchClassification(0, ACMatchClassification::DIM));
578        }
579        last_keyword = i->keyword;
580      }
581    } else {
582      last_keyword.clear();
583    }
584  }
585}
586
587void AutocompleteController::NotifyChanged(bool notify_default_match) {
588  if (delegate_)
589    delegate_->OnResultChanged(notify_default_match);
590  if (done_) {
591    content::NotificationService::current()->Notify(
592        chrome::NOTIFICATION_AUTOCOMPLETE_CONTROLLER_RESULT_READY,
593        content::Source<AutocompleteController>(this),
594        content::NotificationService::NoDetails());
595  }
596}
597
598void AutocompleteController::CheckIfDone() {
599  for (ACProviders::const_iterator i(providers_.begin()); i != providers_.end();
600       ++i) {
601    if (!(*i)->done()) {
602      done_ = false;
603      return;
604    }
605  }
606  done_ = true;
607}
608
609void AutocompleteController::StartExpireTimer() {
610  // Amount of time (in ms) between when the user stops typing and
611  // when we remove any copied entries. We do this from the time the
612  // user stopped typing as some providers (such as SearchProvider)
613  // wait for the user to stop typing before they initiate a query.
614  const int kExpireTimeMS = 500;
615
616  if (result_.HasCopiedMatches())
617    expire_timer_.Start(FROM_HERE,
618                        base::TimeDelta::FromMilliseconds(kExpireTimeMS),
619                        this, &AutocompleteController::ExpireCopiedEntries);
620}
621
622void AutocompleteController::StartStopTimer() {
623  if (!in_stop_timer_field_trial_)
624    return;
625
626  // Amount of time (in ms) between when the user stops typing and
627  // when we send Stop() to every provider.  This is intended to avoid
628  // the disruptive effect of belated omnibox updates, updates that
629  // come after the user has had to time to read the whole dropdown
630  // and doesn't expect it to change.
631  const int kStopTimeMS = 1500;
632  stop_timer_.Start(FROM_HERE,
633                    base::TimeDelta::FromMilliseconds(kStopTimeMS),
634                    base::Bind(&AutocompleteController::Stop,
635                               base::Unretained(this),
636                               false));
637}
638