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

content/browser/web_contents/web_contents_impl.h

 // 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.
 
 #ifndef CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_IMPL_H_
 #define CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_IMPL_H_
 
 #include <stdint.h>
 
 #include <functional>
@@ skipping 777 matching lines @@
                        int active_match_ordinal,
                        bool final_update);
 
   // Modify the counter of connected devices for this WebContents.
   void IncrementBluetoothConnectedDeviceCount();
   void DecrementBluetoothConnectedDeviceCount();
 
   // Called when the WebContents gains or loses a persistent video.
   void SetHasPersistentVideo(bool value);
 
+  // Whether the WebContents has an active fullscreen video that is either using
+  // native or custom controls.

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

I think the description of "effectively fullscreen" from
media_web_contents_observer.h was clearer, and this is the comment more people
are likely to see.  Can you copy some of that here?

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

Done.

+  // |IsFullscreen| must return |true| when this method is called.
+  bool HasActiveEffectivelyFullscreenVideo() const;
+
 #if defined(OS_ANDROID)
   // Called by FindRequestManager when all of the find match rects are in.
   void NotifyFindMatchRectsReply(int version,
                                  const std::vector<gfx::RectF>& rects,
                                  const gfx::RectF& active_rect);
 #endif
 
  private:
   friend class WebContentsObserver;
   friend class WebContents;  // To implement factory methods.
@@ skipping 723 matching lines @@
   // Adds/removes a callback called on creation of each new WebContents.
   static void AddCreatedCallbackForTesting(const CreatedCallback& callback);
   static void RemoveCreatedCallbackForTesting(const CreatedCallback& callback);
 
   DISALLOW_COPY_AND_ASSIGN(FriendZone);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_IMPL_H_