Defer loading of audio/video tags while prerendering.

chrome/renderer/prerender/prerender_webmediaplayer.h

+// Copyright (c) 2011 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_WEBMEDIAPLAYER_H_
+#define CHROME_RENDERER_PRERENDER_PRERENDER_WEBMEDIAPLAYER_H_
+#pragma once
+
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
+#include "content/public/renderer/render_view_observer.h"
+#include "webkit/glue/webmediaplayer_impl.h"
+
+namespace webkit_glue {
+class MediaStreamClient;
+class WebMediaPlayerDelegate;
+}
+
+namespace prerender {
+
+// Substitute for WebMediaPlayerImpl to be used in prerendered pages. Defers
+// the loading of the media till the prerendered page is swapped in.
+class PrerenderWebMediaPlayer
+    : public content::RenderViewObserver,
+      public webkit_glue::WebMediaPlayerImpl {
+ public:
+  PrerenderWebMediaPlayer(
+      content::RenderView* render_view,
+      WebKit::WebMediaPlayerClient* client,
+      base::WeakPtr<webkit_glue::WebMediaPlayerDelegate> delegate,
+      media::FilterCollection* collection,
+      media::MessageLoopFactory* message_loop_factory,
+      webkit_glue::MediaStreamClient* media_stream_client,
+      media::MediaLog* media_log);
+  virtual ~PrerenderWebMediaPlayer();
+
+  // WebMediaPlayer methods:
+  virtual void load(const WebKit::WebURL& url) OVERRIDE;
+  virtual void cancelLoad() OVERRIDE;
+
+ private:
+  // RenderViewObserver method:
+  virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
+
+  virtual void OnSetIsPrerendering(bool is_prerendering);

[dominich, 2011/11/14 19:40:35]

why is this virtual if it's not an OVERRIDE?

[Shishir, 2011/11/14 19:51:53]

Done.

+
+  bool is_prerendering_;
+  scoped_ptr<WebKit::WebURL> url_to_load_;

[dominich, 2011/11/14 19:40:35]

Consider storing a WebKit::WebURL instead of as a pointer. Save the heap
alloc/dealloc.

[Shishir, 2011/11/14 19:51:53]

Its cleaner to create this on load and destroy on cancel. The pointer implicitly
serves as a clean presence check (WebUrl has an empty check but no clear).

+
+  DISALLOW_COPY_AND_ASSIGN(PrerenderWebMediaPlayer);
+};
+
+}  // namespace prerender
+
+#endif  // CHROME_RENDERER_PRERENDER_PRERENDER_WEBMEDIAPLAYER_H_