Propagate audible state from player to the containing tab

content/browser/media/media_web_contents_observer.h

Index: content/browser/media/media_web_contents_observer.h
diff --git a/content/browser/media/media_web_contents_observer.h b/content/browser/media/media_web_contents_observer.h
index 3b451a82800068360fdaad1fb9ca414903c523d2..75efe8505d19083e6345ba7aaf788e10ca53683d 100644
--- a/content/browser/media/media_web_contents_observer.h
+++ b/content/browser/media/media_web_contents_observer.h
@@ -7,11 +7,13 @@
 
 #include "base/compiler_specific.h"
 #include "base/containers/scoped_ptr_hash_map.h"
+#include "base/memory/scoped_ptr.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/web_contents_observer.h"
 
 namespace content {
 
+class AudioMonitorAndroid;
 class BrowserCdmManager;
 class BrowserMediaPlayerManager;
 
@@ -27,6 +29,10 @@ class CONTENT_EXPORT MediaWebContentsObserver : public WebContentsObserver {
   // WebContentsObserver implementations.
   void RenderFrameDeleted(RenderFrameHost* render_frame_host) override;
 
+  // Returns true if at least one player is playing sound and false if
+  // they are all silent.
+  bool IsAudible() const;
+
 #if defined(OS_ANDROID)
   bool OnMessageReceived(const IPC::Message& message,
                          RenderFrameHost* render_frame_host) override;
@@ -54,6 +60,8 @@ class CONTENT_EXPORT MediaWebContentsObserver : public WebContentsObserver {
   typedef base::ScopedPtrHashMap<uintptr_t, BrowserMediaPlayerManager>
       MediaPlayerManagerMap;
   MediaPlayerManagerMap media_player_managers_;
+
+  scoped_ptr<AudioMonitorAndroid> audio_monitor_;
 #endif  // defined(OS_ANDROID)
 
  private: