Make FileStream::Seek async and add FileStream::SeekSync for sync operation

webkit/media/webmediaplayer_impl.cc

 // Copyright (c) 2012 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 "webkit/media/webmediaplayer_impl.h"
 
 #include <limits>
 #include <string>
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/command_line.h"
 #include "base/message_loop_proxy.h"
 #include "base/metrics/histogram.h"
+#include "base/synchronization/waitable_event.h"
 #include "media/base/filter_collection.h"
 #include "media/base/limits.h"
 #include "media/base/media_log.h"
 #include "media/base/media_switches.h"
 #include "media/base/pipeline.h"
 #include "media/base/video_frame.h"
 #include "media/filters/null_audio_renderer.h"
 #include "media/filters/video_renderer_base.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebVideoFrame.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebView.h"
@@ skipping 892 matching lines @@
   return audio_source_provider_;
 }
 
 void WebMediaPlayerImpl::IncrementExternallyAllocatedMemory() {
   DCHECK_EQ(main_loop_, MessageLoop::current());
   incremented_externally_allocated_memory_ = true;
   v8::V8::AdjustAmountOfExternalAllocatedMemory(kPlayerExtraMemory);
 }
 
 }  // namespace webkit_media