content: Cleanup class/struct forward declarations

content/renderer/media/android/webmediaplayer_android.h

 // Copyright 2013 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_RENDERER_MEDIA_ANDROID_WEBMEDIAPLAYER_ANDROID_H_
 #define CONTENT_RENDERER_MEDIA_ANDROID_WEBMEDIAPLAYER_ANDROID_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 20 matching lines @@
 #include "third_party/WebKit/public/platform/WebSize.h"
 #include "third_party/WebKit/public/platform/WebURL.h"
 #include "ui/gfx/geometry/rect_f.h"
 
 namespace base {
 class SingleThreadTaskRunner;
 }
 
 namespace blink {
 class WebContentDecryptionModule;
-class WebContentDecryptionModuleResult;
 class WebFrame;
 class WebMediaPlayerClient;
 class WebMediaPlayerEncryptedMediaClient;
 class WebURL;
 }
 
 namespace cc_blink {
 class WebLayerImpl;
 }
 
 namespace gpu {
 namespace gles2 {
 class GLES2Interface;
 }
-struct MailboxHolder;
 }
 
 namespace media {
 class MediaLog;
-class WebContentDecryptionModuleImpl;
 }
 
 namespace content {
 
 class RendererMediaPlayerManager;
 
 // This class implements blink::WebMediaPlayer by keeping the android
 // media player in the browser process. It listens to all the status changes
 // sent from the browser process and sends playback controls to the media
 // player.
@@ skipping 354 matching lines @@
 
   // NOTE: Weak pointers must be invalidated before all other member variables.
   base::WeakPtrFactory<WebMediaPlayerAndroid> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(WebMediaPlayerAndroid);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_ANDROID_WEBMEDIAPLAYER_ANDROID_H_