Use AudioStreamMonitor to control power save blocking.

content/browser/web_contents/web_contents_impl.cc

Index: content/browser/web_contents/web_contents_impl.cc
diff --git a/content/browser/web_contents/web_contents_impl.cc b/content/browser/web_contents/web_contents_impl.cc
index 501ae9aa0f4ed99da6be0385031b7cc5c55f39de..5c98256548fcedd504bd0a5c58d7cbd1573243e4 100644
--- a/content/browser/web_contents/web_contents_impl.cc
+++ b/content/browser/web_contents/web_contents_impl.cc
@@ -111,6 +111,13 @@
 #include "base/mac/foundation_util.h"
 #endif
 
+// Only do audio stream monitoring for platforms that use it for the tab media
+// indicator UI or the OOM killer.
+#if !defined(OS_ANDROID) && !defined(OS_IOS)
+#define AUDIO_STREAM_MONITORING

[jam, 2014/09/02 19:50:33]

nit: use a boolean member in this class that is initialized through
'!defined(OS_ANDROID) && !defined(OS_IOS)', but don't define ifdef's and use it
through the file. that is confusing and not a standard way of enabling stuff per
platform

[DaleCurtis, 2014/09/04 21:59:06]

I instead plumbing a bit which is defined where this decision is made, so we
don't have multiple clients reimplementing this.  AudioOutputController now
decides whether or not it will monitor and the audio stream monitor keys off of
that.

+#include "content/browser/media/audio_stream_monitor.h"
+#endif
+
 // Cross-Site Navigations
 //
 // If a WebContentsImpl is told to navigate to a different web site (as
@@ -1042,6 +1049,10 @@ void WebContentsImpl::WasShown() {
     rvh->ResizeRectChanged(GetRootWindowResizerRect());
   }
 
+  // Restore power save blocker if there are active video players running.
+  if (!active_media_players_.empty())
+    CreatePowerSaveBlocker();
+
   FOR_EACH_OBSERVER(WebContentsObserver, observers_, WasShown());
 
   should_normally_be_visible_ = true;
@@ -1066,6 +1077,9 @@ void WebContentsImpl::WasHidden() {
     }
   }
 
+  // Release any video power save blockers held as video is not visible.
+  power_save_blocker_.reset();
+
   FOR_EACH_OBSERVER(WebContentsObserver, observers_, WasHidden());
 
   should_normally_be_visible_ = false;
@@ -2388,6 +2402,15 @@ void WebContentsImpl::InsertCSS(const std::string& css) {
       GetMainFrame()->GetRoutingID(), css));
 }
 
+bool WebContentsImpl::WasRecentlyAudible() {
+#if !defined(AUDIO_STREAM_MONITORING)
+  return false;
+#else
+  AudioStreamMonitor* const monitor = AudioStreamMonitor::FromWebContents(this);
+  return monitor ? monitor->WasRecentlyAudible() : false;
+#endif
+}
+
 bool WebContentsImpl::FocusLocationBarByDefault() {
   NavigationEntry* entry = controller_.GetVisibleEntry();
   if (entry && entry->GetURL() == GURL(url::kAboutBlankURL))
@@ -2999,42 +3022,61 @@ void WebContentsImpl::OnUpdateFaviconURL(
                     DidUpdateFaviconURL(candidates));
 }
 
+void WebContentsImpl::CreatePowerSaveBlocker() {
+  DCHECK(!power_save_blocker_);
+  DCHECK(!active_media_players_.empty());
+  power_save_blocker_ = PowerSaveBlocker::Create(
+      PowerSaveBlocker::kPowerSaveBlockPreventDisplaySleep, "Playing Video");
+#if defined(OS_ANDROID)
+  static_cast<PowerSaveBlockerImpl*>(power_save_blocker_.get())
+      ->InitDisplaySleepBlocker(GetView()->GetNativeView());
+#endif
+}
+
 void WebContentsImpl::OnMediaPlayingNotification(int64 player_cookie,
                                                  bool has_video,
                                                  bool has_audio) {
 #if !defined(OS_CHROMEOS)
-  scoped_ptr<PowerSaveBlocker> blocker;
-  if (has_video) {
-    blocker = PowerSaveBlocker::Create(
-        PowerSaveBlocker::kPowerSaveBlockPreventDisplaySleep, "Playing video");
-#if defined(OS_ANDROID)
-    static_cast<PowerSaveBlockerImpl*>(blocker.get())
-        ->InitDisplaySleepBlocker(GetView()->GetNativeView());
+#if defined(AUDIO_STREAM_MONITORING)
+  // Don't handle audio if audio level analysis is available.
+  if (!has_video)
+    return;
 #endif
-  } else if (has_audio) {
-    blocker = PowerSaveBlocker::Create(

[miu, 2014/09/02 21:04:39]

I'm not sure the blocker is set up correctly for platforms where
AUDIO_STREAM_MONITORING is not defined.  It seems like if only audio is playing,
we will be creating a "PreventDisplaySleep" blocker.  Also, the !IsHidden()
check (a dozen LOC down) isn't relevant for audio, right?

Given my comments elsewhere (in ASM.cc about moving the PowerSaveBlocker into
WebContentsImpl), perhaps you might retain this code and call this method (with
has_audio=true) from WCImpl::NotifyNavigationStateChanged()?

[DaleCurtis, 2014/09/03 18:48:55]

It ends up being correct since Androids PowerSaveBlocker is the same regardless
of type, but I agree that it's hacky. I'll see what I can do about making this
clearer.

-        PowerSaveBlocker::kPowerSaveBlockPreventAppSuspension, "Playing audio");
-  }
 
-  if (blocker) {
-    uintptr_t key = reinterpret_cast<uintptr_t>(render_frame_message_source_);
-    if (!power_save_blockers_.contains(key)) {
-      power_save_blockers_.add(key,
-                               make_scoped_ptr(new PowerSaveBlockerMapEntry));
-    }
-    PowerSaveBlockerMapEntry* map_entry =
-        power_save_blockers_.get(key);
-    map_entry->set(player_cookie, blocker.Pass());
-  }
+  // Track current status to see if we need to create a new blocker.
+  const bool had_no_player = active_media_players_.empty();
+
+  // Store tracking entries based on the RenderFrameHost.
+  const uintptr_t key =
+      reinterpret_cast<uintptr_t>(render_frame_message_source_);
+
+  ActiveMediaPlayerMap::iterator it = active_media_players_.find(key);
+  if (it != active_media_players_.end())
+    it->second++;
+  else
+    active_media_players_[key] = 1;
+
+  // If we're not hidden and just created a new video player, create a blocker.
+  if (had_no_player && !active_media_players_.empty() && !IsHidden())
+    CreatePowerSaveBlocker();
 #endif  // !defined(OS_CHROMEOS)
 }
 
 void WebContentsImpl::OnMediaPausedNotification(int64 player_cookie) {
 #if !defined(OS_CHROMEOS)
-  uintptr_t key = reinterpret_cast<uintptr_t>(render_frame_message_source_);
-  PowerSaveBlockerMapEntry* map_entry = power_save_blockers_.get(key);
-  if (map_entry)
-    map_entry->erase(player_cookie);
+  ActiveMediaPlayerMap::iterator it = active_media_players_.find(
+      reinterpret_cast<uintptr_t>(render_frame_message_source_));
+  if (it == active_media_players_.end())
+    return;
+  it->second--;
+  DCHECK_GE(it->second, 0);
+  // If there are no more active players in this RenderFrameHost, remove entry.
+  if (!it->second)
+    active_media_players_.erase(it);
+  // If there are no more active players at all, clear the power blocker.
+  if (active_media_players_.empty()) {
+    power_save_blocker_.reset();
+  }
 #endif  // !defined(OS_CHROMEOS)
 }
 
@@ -4203,17 +4245,22 @@ BrowserPluginEmbedder* WebContentsImpl::GetBrowserPluginEmbedder() const {
 void WebContentsImpl::ClearPowerSaveBlockers(
     RenderFrameHost* render_frame_host) {
 #if !defined(OS_CHROMEOS)
-  uintptr_t key = reinterpret_cast<uintptr_t>(render_frame_host);
-  scoped_ptr<PowerSaveBlockerMapEntry> map_entry =
-      power_save_blockers_.take_and_erase(key);
-  if (map_entry)
-    map_entry->clear();
+  ActiveMediaPlayerMap::iterator it = active_media_players_.find(
+      reinterpret_cast<uintptr_t>(render_frame_message_source_));
+  if (it == active_media_players_.end())
+    return;
+  active_media_players_.erase(it);
+
+  // If there are no more active players at all, clear the power blocker.
+  if (active_media_players_.empty())
+    power_save_blocker_.reset();
 #endif
 }
 
 void WebContentsImpl::ClearAllPowerSaveBlockers() {
 #if !defined(OS_CHROMEOS)
-  power_save_blockers_.clear();
+  active_media_players_.clear();
+  power_save_blocker_.reset();
 #endif
 }