Defer media playback in background tabs.

chrome/renderer/prerender/prerender_media_load_deferrer.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 CHROME_RENDERER_PRERENDER_PRERENDER_MEDIA_LOAD_DEFERRER_H_
-#define CHROME_RENDERER_PRERENDER_PRERENDER_MEDIA_LOAD_DEFERRER_H_
-
-#include "base/callback.h"
-#include "content/public/renderer/render_frame_observer.h"
-
-namespace prerender {
-
-// Defers media player loading in prerendered pages until the prerendered page
-// is swapped in.
-class PrerenderMediaLoadDeferrer : public content::RenderFrameObserver {
- public:
-  // Will run |closure| to continue loading the media resource once the page is
-  // swapped in.
-  PrerenderMediaLoadDeferrer(content::RenderFrame* render_frame,
-                             const base::Closure& closure);
-  ~PrerenderMediaLoadDeferrer() override;
-
- private:
-  // RenderFrameObserver method:
-  bool OnMessageReceived(const IPC::Message& message) override;
-
-  void OnSetIsPrerendering(bool is_prerendering);
-
-  bool is_prerendering_;
-  base::Closure continue_loading_cb_;
-
-  DISALLOW_COPY_AND_ASSIGN(PrerenderMediaLoadDeferrer);
-};
-
-}  // namespace prerender
-
-#endif  // CHROME_RENDERER_PRERENDER_PRERENDER_MEDIA_LOAD_DEFERRER_H_