Defer media playback in background tabs.

chrome/renderer/prerender/prerender_media_load_deferrer.cc

-// 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.
-
-#include "chrome/renderer/prerender/prerender_media_load_deferrer.h"
-
-#include "base/callback_helpers.h"
-#include "chrome/common/prerender_messages.h"
-
-namespace prerender {
-
-PrerenderMediaLoadDeferrer::PrerenderMediaLoadDeferrer(
-    content::RenderFrame* render_frame,
-    const base::Closure& closure)
-    : RenderFrameObserver(render_frame),
-      is_prerendering_(true),
-      continue_loading_cb_(closure) {
-  DCHECK(!continue_loading_cb_.is_null());
-}
-
-PrerenderMediaLoadDeferrer::~PrerenderMediaLoadDeferrer() {}
-
-bool PrerenderMediaLoadDeferrer::OnMessageReceived(
-    const IPC::Message& message) {
-  IPC_BEGIN_MESSAGE_MAP(PrerenderMediaLoadDeferrer, message)
-    IPC_MESSAGE_HANDLER(PrerenderMsg_SetIsPrerendering, OnSetIsPrerendering)
-  IPC_END_MESSAGE_MAP()
-
-  return false;
-}
-
-void PrerenderMediaLoadDeferrer::OnSetIsPrerendering(bool is_prerendering) {
-  // Prerendering can only be enabled prior to a RenderFrame's first
-  // navigation, so no PrerenderMediaLoadDeferrer should see the notification
-  // that enables prerendering.
-  DCHECK(!is_prerendering);
-  if (!is_prerendering_ || is_prerendering)
-    return;
-
-  is_prerendering_ = false;
-  base::ResetAndReturn(&continue_loading_cb_).Run();
-}
-
-}  // namespace prerender