Fix wrong timing when audio is muted.

media/audio/audio_output_mixer.h

Index: media/audio/audio_output_mixer.h
===================================================================
--- media/audio/audio_output_mixer.h	(revision 140286)
+++ media/audio/audio_output_mixer.h	(working copy)
@@ -77,7 +77,12 @@
 
   // Temporary buffer used when mixing. Allocated in the constructor
   // to avoid constant allocation/deallocation in the callback.
+  // Low-level multimedia code may work better when data is aligned, as it can
+  // use SSEx/AVX intrinsics. We don't want to use platform-specific aligned
+  // memory allocator, it does not work well with scoped_ptr. Just allocate
+  // slightly more and use raw pointer to the aligned data.
   scoped_array<uint8> mixer_data_;
+  uint8* aligned_mixer_data_;
 
   // Used to post delayed tasks to ourselves that we cancel inside Shutdown().
   base::WeakPtrFactory<AudioOutputMixer> weak_this_;