Implement MediaMetadata artwork in content

content/browser/media/session/media_session.cc

Index: content/browser/media/session/media_session.cc
diff --git a/content/browser/media/session/media_session.cc b/content/browser/media/session/media_session.cc
index 5c63545c3c4bf2d3195d7f52e6f15bab548e46c5..588f6b5789541e26fc8459876176fd33b1f87872 100644
--- a/content/browser/media/session/media_session.cc
+++ b/content/browser/media/session/media_session.cc
@@ -58,6 +58,11 @@ MediaSession::~MediaSession() {
   DCHECK(audio_focus_state_ == State::INACTIVE);
 }
 
+void MediaSession::SetMetadata(const MediaMetadata& metadata) {
+  metadata_ = metadata;
+  static_cast<WebContentsImpl*>(web_contents())->OnMediaSessionStateChanged();

[palmer, 2016/06/14 22:06:31]

What guarantees that this cast is safe/correct?

[Zhiqiang Zhang (Slow), 2016/06/20 18:26:49]

WebContentsImpl is the only subclass of WebContents, and MediaSession is valid
as long as WebContents lives, so this cast is safe. Another example is
MediaSession::UpdateWebContents().

+}
+
 bool MediaSession::AddPlayer(MediaSessionObserver* observer,
                              int player_id,
                              Type type) {