[chromecast] Pass media task runner to MediaPipelineBackendManager.

chromecast/browser/cast_content_browser_client.cc

Index: chromecast/browser/cast_content_browser_client.cc
diff --git a/chromecast/browser/cast_content_browser_client.cc b/chromecast/browser/cast_content_browser_client.cc
index dc5902ac7e67d80b42745ebef9874ac48bb4bbe7..4fb76fd20a43c47cae78eac5ed23a8f419d2a493 100644
--- a/chromecast/browser/cast_content_browser_client.cc
+++ b/chromecast/browser/cast_content_browser_client.cc
@@ -101,7 +101,8 @@ scoped_ptr<CastService> CastContentBrowserClient::CreateCastService(
     content::BrowserContext* browser_context,
     PrefService* pref_service,
     net::URLRequestContextGetter* request_context_getter,
-    media::VideoPlaneController* video_plane_controller) {
+    media::VideoPlaneController* video_plane_controller,
+    media::MediaPipelineBackendManager* media_pipeline_backend_manager) {
   return make_scoped_ptr(new CastServiceSimple(browser_context, pref_service));
 }
 
@@ -109,8 +110,10 @@ scoped_ptr<CastService> CastContentBrowserClient::CreateCastService(
 scoped_ptr<media::MediaPipelineBackend>
 CastContentBrowserClient::CreateMediaPipelineBackend(
     const media::MediaPipelineDeviceParams& params) {
+  DCHECK(cast_browser_main_parts_);
   return make_scoped_ptr(
-      media::MediaPipelineBackendManager::CreateMediaPipelineBackend(params));
+      cast_browser_main_parts_->media_pipeline_backend_manager()
+          ->CreateMediaPipelineBackend(params));
 }
 
 media::MediaResourceTracker*