Reland: Use a shared thread for media operations (round 3).

webkit/renderer/media/webmediaplayer_params.h

Index: webkit/renderer/media/webmediaplayer_params.h
diff --git a/webkit/renderer/media/webmediaplayer_params.h b/webkit/renderer/media/webmediaplayer_params.h
index 893cae7c6fbde136107bac08bed5023116a36494..62a5ce187c7e1b4d444ab8f09bca01541ffa2e1d 100644
--- a/webkit/renderer/media/webmediaplayer_params.h
+++ b/webkit/renderer/media/webmediaplayer_params.h
@@ -8,6 +8,10 @@
 #include "base/memory/ref_counted.h"
 #include "media/filters/gpu_video_decoder.h"
 
+namespace base {
+class MessageLoopProxy;
+}
+
 namespace media {
 class AudioRendererSink;
 class MediaLog;
@@ -19,13 +23,19 @@ namespace webkit_media {
 // to plumb arguments through various abstraction layers.
 class WebMediaPlayerParams {
  public:
-  // |media_log| is the only required parameter; all others may be null.
+  // |message_loop_proxy| and |media_log| are the only required parameters;
+  // all others may be null.
   WebMediaPlayerParams(
+      const scoped_refptr<base::MessageLoopProxy>& message_loop_proxy,
       const scoped_refptr<media::AudioRendererSink>& audio_renderer_sink,
       const scoped_refptr<media::GpuVideoDecoder::Factories>& gpu_factories,
       const scoped_refptr<media::MediaLog>& media_log);
   ~WebMediaPlayerParams();
 
+  const scoped_refptr<base::MessageLoopProxy>& message_loop_proxy() const {
+    return message_loop_proxy_;
+  }
+
   const scoped_refptr<media::AudioRendererSink>& audio_renderer_sink() const {
     return audio_renderer_sink_;
   }
@@ -40,6 +50,7 @@ class WebMediaPlayerParams {
   }
 
  private:
+  scoped_refptr<base::MessageLoopProxy> message_loop_proxy_;
   scoped_refptr<media::AudioRendererSink> audio_renderer_sink_;
   scoped_refptr<media::GpuVideoDecoder::Factories> gpu_factories_;
   scoped_refptr<media::MediaLog> media_log_;