Decouple MediaSession messages from WebContents (full patch)

chromecast/browser/cast_media_blocker.h

Index: chromecast/browser/cast_media_blocker.h
diff --git a/chromecast/browser/cast_media_blocker.h b/chromecast/browser/cast_media_blocker.h
index b3350603f7b1fb448130768b7a7eb26cca37b899..727c50344d294d9a605254cacbd4808209090c70 100644
--- a/chromecast/browser/cast_media_blocker.h
+++ b/chromecast/browser/cast_media_blocker.h
@@ -5,26 +5,23 @@
 #ifndef CHROMECAST_BROWSER_CAST_MEDIA_BLOCKER_H_
 #define CHROMECAST_BROWSER_CAST_MEDIA_BLOCKER_H_
 
-#include "base/macros.h"
+#include "base/callback.h"
 #include "base/callback_forward.h"
-#include "content/public/browser/web_contents_observer.h"
-
-namespace content {
-class WebContents;
-}  // namespace content
+#include "base/macros.h"
+#include "content/public/browser/media_session_observer.h"
 
 namespace chromecast {
 namespace shell {
 
 // This class implements a blocking mode for web applications and is used in
 // Chromecast internal code. Media is unblocked by default.
-class CastMediaBlocker : public content::WebContentsObserver {
+class CastMediaBlocker : public content::MediaSessionObserver {
  public:
-  explicit CastMediaBlocker(content::WebContents* web_contents);
+  explicit CastMediaBlocker(content::MediaSession* media_session);
 
   // Constructor for test. |suspend_cb| and |resume_cb| will be called when
   // Suspend() and Resume() are called.
-  CastMediaBlocker(content::WebContents* web_contents,
+  CastMediaBlocker(content::MediaSession* media_session,
                    const base::Closure& suspend_cb,
                    const base::Closure& resume_cb);