Provide a WebContents API to discover the playback of a fullscreen video.

content/browser/web_contents/web_contents_impl.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/web_contents/web_contents_impl.h"
 
 #include <stddef.h>
 
 #include <cmath>
 #include <utility>
@@ skipping 4238 matching lines @@
 }
 
 bool WebContentsImpl::HideDownloadUI() const {
   return is_overlay_content_;
 }
 
 bool WebContentsImpl::HasPersistentVideo() const {
   return has_persistent_video_;
 }
 
+bool WebContentsImpl::HasActiveEffectivelyFullscreenVideo() const {
+  return media_web_contents_observer_->HasActiveEffectivelyFullscreenVideo();

[Charlie Reis, 2017/02/23 00:18:08]

I found this pretty weird at first glance-- that WebContents would implement a
method by asking one of its observers.  (Seems oddly circular.)

I think I understand now that MediaWebContentsObserver is really more of its own
class that manages some state (and happens to be a WebContentsObserver to get
its job done).  In that sense, maybe that class would make more sense if it
didn't have WebContentsObserver in its name?

Anyway, it's not a problem for this CL, and not something I feel too strongly
about.  Just a way to possibly reduce confusion in the future.

[mlamouri (slow - plz ping), 2017/02/23 13:34:19]

Ack

+}
+
 bool WebContentsImpl::IsFocusedElementEditable() {
   RenderFrameHostImpl* frame = GetFocusedFrame();
   return frame && frame->has_focused_editable_element();
 }
 
 void WebContentsImpl::ClearFocusedElement() {
   if (auto* frame = GetFocusedFrame())
     frame->ClearFocusedElement();
 }
 
@@ skipping 1160 matching lines @@
     RenderViewHost* render_view_host = RenderViewHost::From(render_widget_host);
     if (!render_view_host)
       continue;
     render_view_host_set.insert(render_view_host);
   }
   for (RenderViewHost* render_view_host : render_view_host_set)
     render_view_host->OnWebkitPreferencesChanged();
 }
 
 }  // namespace content