Fixed the audio backgrounding bug

content/browser/renderer_host/render_process_host_impl.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Represents the browser side of the browser <--> renderer communication
 // channel. There will be one RenderProcessHost per renderer process.
 
 #include "content/browser/renderer_host/render_process_host_impl.h"
 
 #include <algorithm>
@@ skipping 1074 matching lines @@
   if (visible_widgets_ == 0) {
     DCHECK(!backgrounded_);
     SetBackgrounded(true);
   }
 }
 
 int RenderProcessHostImpl::VisibleWidgetCount() const {
   return visible_widgets_;
 }
 
+void RenderProcessHostImpl::AudioStopped() {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+
+  // If the backgrounding was skipped because audio was playing, we background

[gab, 2015/06/30 13:41:41]

-we (in general we try to avoid "we" in comments), e.g.

// If backgrounding was skipped because audio was playing, background the tab
now.

[sebsg, 2015/07/02 12:58:08]

Done.

+  // the tab.
+  if (backgrounded_)
+    SetBackgrounded(true);
+}
+
+void RenderProcessHostImpl::AudioStarted() {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+
+  // If audio starts from a backgrounded tab, we un-background it.

[gab, 2015/06/30 13:41:41]

// If audio starts playing from a backgrounded tab, unbackground it.

[sebsg, 2015/07/02 12:58:08]

Done.

+  if (backgrounded_) {
+    SetBackgrounded(false);
+
+    // Since it's not a visible tab, we need to set it to backgrounded so that
+    // it is backgrounded again when the video finishes.

[gab, 2015/06/30 13:41:41]

// Since it's not a visible tab, it needs to be marked for backgrounding again
so that it is re-backgrounded if/when the audio stops.

[sebsg, 2015/07/02 12:58:09]

Done.

+    SetBackgrounded(true);
+  }
+}
+
 bool RenderProcessHostImpl::IsForGuestsOnly() const {
   return is_for_guests_only_;
 }
 
 StoragePartition* RenderProcessHostImpl::GetStoragePartition() const {
   return storage_partition_impl_;
 }
 
 static void AppendCompositorCommandLineFlags(base::CommandLine* command_line) {
   if (IsPropertyTreeVerificationEnabled())
@@ skipping 1125 matching lines @@
   mojo_application_host_->WillDestroySoon();
 
   Send(new ChildProcessMsg_Shutdown());
 }
 
 void RenderProcessHostImpl::SuddenTerminationChanged(bool enabled) {
   SetSuddenTerminationAllowed(enabled);
 }
 
 void RenderProcessHostImpl::SetBackgrounded(bool backgrounded) {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
   TRACE_EVENT1("renderer_host", "RenderProcessHostImpl::SetBackgrounded",
                "backgrounded", backgrounded);
   // Note: we always set the backgrounded_ value.  If the process is NULL
   // (and hence hasn't been created yet), we will set the process priority
   // later when we create the process.
   backgrounded_ = backgrounded;
   if (!child_process_launcher_.get() || child_process_launcher_->IsStarting())
     return;
 
   // Don't background processes which have active audio streams.
@@ skipping 262 matching lines @@
 void RenderProcessHostImpl::GetAudioOutputControllers(
     const GetAudioOutputControllersCallback& callback) const {
   audio_renderer_host()->GetOutputControllers(callback);
 }
 
 BluetoothDispatcherHost* RenderProcessHostImpl::GetBluetoothDispatcherHost() {
   return bluetooth_dispatcher_host_.get();
 }
 
 }  // namespace content