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/metrics/field_trial_synchronizer.h" 6 7#include "base/bind.h" 8#include "base/logging.h" 9#include "base/threading/thread.h" 10#include "chrome/common/chrome_constants.h" 11#include "chrome/common/render_messages.h" 12#include "chrome/common/variations/variations_util.h" 13#include "content/public/browser/browser_thread.h" 14#include "content/public/browser/render_process_host.h" 15 16using content::BrowserThread; 17 18namespace { 19 20// This singleton instance should be constructed during the single threaded 21// portion of main(). It initializes globals to provide support for all future 22// calls. This object is created on the UI thread, and it is destroyed after 23// all the other threads have gone away. 24FieldTrialSynchronizer* g_field_trial_synchronizer = NULL; 25 26} // namespace 27 28FieldTrialSynchronizer::FieldTrialSynchronizer() { 29 DCHECK(g_field_trial_synchronizer == NULL); 30 g_field_trial_synchronizer = this; 31 base::FieldTrialList::AddObserver(this); 32 33 chrome_variations::SetChildProcessLoggingVariationList(); 34} 35 36void FieldTrialSynchronizer::NotifyAllRenderers( 37 const std::string& field_trial_name, 38 const std::string& group_name) { 39 // To iterate over RenderProcessHosts, or to send messages to the hosts, we 40 // need to be on the UI thread. 41 DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI)); 42 43 for (content::RenderProcessHost::iterator it( 44 content::RenderProcessHost::AllHostsIterator()); 45 !it.IsAtEnd(); it.Advance()) { 46 it.GetCurrentValue()->Send( 47 new ChromeViewMsg_SetFieldTrialGroup(field_trial_name, group_name)); 48 } 49} 50 51void FieldTrialSynchronizer::OnFieldTrialGroupFinalized( 52 const std::string& field_trial_name, 53 const std::string& group_name) { 54 CHECK(!field_trial_name.empty() && !group_name.empty()); 55 BrowserThread::PostTask( 56 BrowserThread::UI, FROM_HERE, 57 base::Bind(&FieldTrialSynchronizer::NotifyAllRenderers, 58 this, 59 field_trial_name, 60 group_name)); 61 chrome_variations::SetChildProcessLoggingVariationList(); 62} 63 64FieldTrialSynchronizer::~FieldTrialSynchronizer() { 65 base::FieldTrialList::RemoveObserver(this); 66 g_field_trial_synchronizer = NULL; 67} 68