NOT FOR LANDING Implement WebMediaSession

content/browser/android/web_contents_observer_proxy.cc

Index: content/browser/android/web_contents_observer_proxy.cc
diff --git a/content/browser/android/web_contents_observer_proxy.cc b/content/browser/android/web_contents_observer_proxy.cc
index adfa2aaaf4d67dd4c889f9621dfcdcecf5acd30f..e856d8e4ef79b382305bdb5041a4cf88aa5e0c9d 100644
--- a/content/browser/android/web_contents_observer_proxy.cc
+++ b/content/browser/android/web_contents_observer_proxy.cc
@@ -293,6 +293,10 @@ void WebContentsObserverProxy::MediaSessionStateChanged(bool is_controllable,
 
   ScopedJavaLocalRef<jobject> obj(java_observer_);
 
+  // TODO(philipj): This is where we cross from content/ to chrome/, i.e. where
+  // Chrome and Opera will have different UIs. Need to send all relevant
+  // information here, i.e. the metadata for Blink-created media sessions, and
+  // the tab title and other information for the default media session.

[mlamouri (slow - plz ping), 2015/08/24 12:55:24]

tab title should be available from WebContents. I don't think we need to send
that here.

[whywhat, 2015/08/24 14:39:18]

It might make sense to send media session metadata which would be filled with
the tab title by default I guess.

[philipj_slow, 2015/08/26 07:39:48]

Right, when I wrote this comment, I was thinking that we would have a
content::MediaSession that basically just maps to Android's MediaSession, so
that it becomes the job of some other class to monitor all of the media players
in a tab and to come up with metadata since none can be provided by scripts in
this case.

However, we might consider what should happen when a script creates a
MediaSession put doesn't provide any metadata. If the fallback in this case can
be the same as for the default media session, then indeed we do not need to ever
send in a tab title at this level, it would just be the in the code that creates
the notification.

   Java_WebContentsObserverProxy_mediaSessionStateChanged(
       env, obj.obj(), is_controllable, is_suspended);
 }