Checking in media::FFmpegGlue and some common FFmpeg code.

media/filters/ffmpeg_common.h

+// Copyright (c) 2009 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.
+
+// Used for FFmpeg error codes.
+#include <cerrno>
+
+#include "base/compiler_specific.h"
+
+// Include FFmpeg header files.
+extern "C" {
+// Temporarily disable possible loss of data warning.
+// TODO(scherkus): fix and upstream the compiler warnings.
+MSVC_PUSH_DISABLE_WARNING(4244);
+#include "third_party/ffmpeg/include/libavcodec/avcodec.h"
+#include "third_party/ffmpeg/include/libavformat/avformat.h"
+MSVC_POP_WARNING();
+}  // extern "C"
+
+namespace media {
+
+// MediaFormat key identifying the CodecID.
+extern const char kFFmpegCodecID[];
+
+// FFmpeg MIME types.
+namespace mime_type {
+
+extern const char kFFmpegAudio[];
+extern const char kFFmpegVideo[];
+
+}  // namespace mime_type
+
+}  // namespace media