Plugin Power Saver: Mute throttled plugins.

content/renderer/pepper/plugin_instance_throttler_impl.h

Index: content/renderer/pepper/plugin_instance_throttler_impl.h
diff --git a/content/renderer/pepper/plugin_instance_throttler_impl.h b/content/renderer/pepper/plugin_instance_throttler_impl.h
index b223cd26b613c65c5de327ad5676ec3b2e98e553..0bcad2f60dcade53727b175c2fac0b4ac3694803 100644
--- a/content/renderer/pepper/plugin_instance_throttler_impl.h
+++ b/content/renderer/pepper/plugin_instance_throttler_impl.h
@@ -8,9 +8,11 @@
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
+#include "base/timer/timer.h"
 #include "content/common/content_export.h"
 #include "content/public/renderer/plugin_instance_throttler.h"
 #include "ppapi/shared_impl/ppb_view_shared.h"
+#include "third_party/skia/include/core/SkBitmap.h"
 
 namespace blink {
 class WebInputEvent;
@@ -36,6 +38,7 @@ class CONTENT_EXPORT PluginInstanceThrottlerImpl
   void MarkPluginEssential(PowerSaverUnthrottleMethod method) override;
   void SetHiddenForPlaceholder(bool hidden) override;
   blink::WebPlugin* GetWebPlugin() const override;
+  void NotifyAudioThrottled() override;
 
   void SetWebPlugin(blink::WebPlugin* web_plugin);
 
@@ -80,6 +83,7 @@ class CONTENT_EXPORT PluginInstanceThrottlerImpl
   // simply suspend the plugin where it's at. Chosen arbitrarily.
   static const int kMaximumFramesToExamine;
 
+  void AudioThrottledFrameTimeout();
   void EngageThrottle();
 
   ThrottlerState state_;
@@ -88,12 +92,21 @@ class CONTENT_EXPORT PluginInstanceThrottlerImpl
 
   blink::WebPlugin* web_plugin_;
 
+  // Holds a reference to the last received frame. This doesn't actually copy
+  // the pixel data, but rather increments the reference count to the pixels.
+  SkBitmap last_received_frame_;
+
   // Number of consecutive interesting frames we've encountered.
   int consecutive_interesting_frames_;
 
   // Number of frames we've examined to find a keyframe.
   int frames_examined_;
 
+  // Video plugins with throttled audio often stop generating frames.
+  // This timer is so we don't wait forever for candidate poster frames.
+  bool audio_throttled_;
+  base::DelayTimer<PluginInstanceThrottlerImpl> audio_throttled_frame_timeout_;
+
   ObserverList<Observer> observer_list_;
 
   base::WeakPtrFactory<PluginInstanceThrottlerImpl> weak_factory_;