Refactor some code that depends on FFmpeg

media/ffmpeg/ffmpeg_common.cc

-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Copyright (c) 2010 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 "media/filters/ffmpeg_common.h"
+#include "media/ffmpeg/ffmpeg_common.h"
 
 namespace media {
 
 FFmpegLock::FFmpegLock() {
 }
 
 FFmpegLock::~FFmpegLock() {
 }
 
 Lock& FFmpegLock::lock() {
   return lock_;
 }
 
 namespace mime_type {
 
 const char kFFmpegAudio[] = "audio/x-ffmpeg";
 const char kFFmpegVideo[] = "video/x-ffmpeg";
 
 }  // namespace mime_type
 
 }  // namespace media