Fix a PowerSaveBlocker leak in WebContentsImpl.

content/browser/web_contents/web_contents_impl.h

Index: content/browser/web_contents/web_contents_impl.h
===================================================================
--- content/browser/web_contents/web_contents_impl.h	(revision 287233)
+++ content/browser/web_contents/web_contents_impl.h	(working copy)
@@ -897,7 +897,7 @@
   // Clear |render_frame_host|'s PowerSaveBlockers.
   void ClearPowerSaveBlockers(RenderFrameHost* render_frame_host);
 
-  // Clear all PowerSaveBlockers, leave power_save_blocker_ empty.
+  // Clear all PowerSaveBlockers, leave |power_save_blocker_| empty.
   void ClearAllPowerSaveBlockers();
 
   // Helper function to invoke WebContentsDelegate::GetSizeForNewRenderView().
@@ -964,12 +964,16 @@
 
   // Helper classes ------------------------------------------------------------
 
+#if !defined(OS_CHROMEOS)
   // Maps the RenderFrameHost to its media_player_cookie and PowerSaveBlocker
   // pairs. Key is the RenderFrameHost, value is the map which maps
   // player_cookie on to PowerSaveBlocker.
+  //
+  // ChromeOS does its own detection of audio and video.
   typedef std::map<RenderFrameHost*, std::map<int64, PowerSaveBlocker*> >
       PowerSaveBlockerMap;
   PowerSaveBlockerMap power_save_blockers_;
+#endif
 
   // Manages the frame tree of the page and process swaps in each node.
   FrameTree frame_tree_;