Refactor media out of WebContentsImpl to MediaWebContentsObserver.

chromecast/browser/cast_content_window.cc

Index: chromecast/browser/cast_content_window.cc
diff --git a/chromecast/browser/cast_content_window.cc b/chromecast/browser/cast_content_window.cc
index aa3d6837e318f8aa22df69780555d35820f3076e..aadf261f21c7b42fc2a128b9878f454a8e036199 100644
--- a/chromecast/browser/cast_content_window.cc
+++ b/chromecast/browser/cast_content_window.cc
@@ -122,11 +122,11 @@ void CastContentWindow::DidFirstVisuallyNonEmptyPaint() {
   metrics::CastMetricsHelper::GetInstance()->LogTimeToFirstPaint();
 }
 
-void CastContentWindow::MediaPaused() {
+void CastContentWindow::MediaPaused(const content::MediaPlayerId& id) {
   metrics::CastMetricsHelper::GetInstance()->LogMediaPause();
 }
 
-void CastContentWindow::MediaStartedPlaying() {
+void CastContentWindow::MediaStartedPlaying(const content::MediaPlayerId& id) {
   metrics::CastMetricsHelper::GetInstance()->LogMediaPlay();
 }