Defer loading of audio/video tags while prerendering.

chrome/renderer/prerender/prerender_webmediaplayer.cc

+// 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.
+
+#include "chrome/renderer/prerender/prerender_webmediaplayer.h"
+
+#include "chrome/common/render_messages.h"
+#include "content/public/renderer/render_view.h"
+#include "media/base/filter_collection.h"
+#include "media/base/media_log.h"
+#include "media/base/pipeline_impl.h"
+#include "third_party/WebKit/Source/WebKit/chromium/public/WebURL.h"
+
+namespace prerender {
+
+PrerenderWebMediaPlayer::PrerenderWebMediaPlayer(
+    content::RenderView* render_view,
+    WebKit::WebMediaPlayerClient* client,
+    media::FilterCollection* collection,
+    media::MessageLoopFactory* message_loop_factory,
+    webkit_glue::MediaStreamClient* media_stream_client,
+    media::MediaLog* media_log)
+    : RenderViewObserver(render_view),
+      WebMediaPlayerImpl(client,
+                         collection,
+                         message_loop_factory,
+                         media_stream_client,
+                         media_log),
+      is_prerendering_(true) {
+}
+
+PrerenderWebMediaPlayer::~PrerenderWebMediaPlayer() {}
+
+void PrerenderWebMediaPlayer::load(const WebKit::WebURL& url) {
+  if (is_prerendering_) {
+    url_to_load_.reset(new WebKit::WebURL(url));
+    return;
+  }
+  WebMediaPlayerImpl::load(url);
+}
+
+void PrerenderWebMediaPlayer::cancelLoad() {
+  if (is_prerendering_) {
+    url_to_load_.reset(NULL);
+    return;
+  }
+  WebMediaPlayerImpl::cancelLoad();
+}
+
+bool PrerenderWebMediaPlayer::OnMessageReceived(const IPC::Message& message) {
+  IPC_BEGIN_MESSAGE_MAP(PrerenderWebMediaPlayer, message)
+    IPC_MESSAGE_HANDLER(ChromeViewMsg_SetIsPrerendering, OnSetIsPrerendering)
+  IPC_END_MESSAGE_MAP()
+
+  return false;
+}
+
+void PrerenderWebMediaPlayer::OnSetIsPrerendering(bool is_prerendering) {
+  // Prerendering can only be enabled prior to a RenderView's first
+  // navigation, so no PrerenderWebMediaPlayer should see the notification
+  // that enables prerendering.
+  DCHECK(!is_prerendering);
+  if (is_prerendering_ && !is_prerendering) {
+    is_prerendering_ = false;
+    if (url_to_load_.get()) {
+      load(*url_to_load_);
+    }
+  }
+}
+
+} // namespace prerender