Remove VideoDecoder::PrepareForShutdownHack() and friends.

media/filters/gpu_video_decoder.h

Index: media/filters/gpu_video_decoder.h
diff --git a/media/filters/gpu_video_decoder.h b/media/filters/gpu_video_decoder.h
index 0a65379cee8aa68919c60aa396dbd7bee6bff0bb..67dcfd7827d149c015d34b1847eaa851511dac5e 100644
--- a/media/filters/gpu_video_decoder.h
+++ b/media/filters/gpu_video_decoder.h
@@ -70,7 +70,6 @@ class MEDIA_EXPORT GpuVideoDecoder
   virtual void Reset(const base::Closure& closure) OVERRIDE;
   virtual void Stop(const base::Closure& closure) OVERRIDE;
   virtual bool HasAlpha() const OVERRIDE;
-  virtual void PrepareForShutdownHack() OVERRIDE;
 
   // VideoDecodeAccelerator::Client implementation.
   virtual void NotifyInitializeDone() OVERRIDE;
@@ -215,10 +214,6 @@ class MEDIA_EXPORT GpuVideoDecoder
   int64 next_picture_buffer_id_;
   int64 next_bitstream_buffer_id_;
 
-  // Indicates PrepareForShutdownHack()'s been called.  Makes further calls to
-  // this class not require the render thread's loop to be processing.
-  bool shutting_down_;
-
   // Indicates decoding error occurred.
   bool error_occured_;