Revert 148024 - [cros] Implement WebM encoder/muxer for animated avatar capture.

media/webm/chromeos/ebml_writer.h

-// 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.
-
-#ifndef MEDIA_WEBM_CHROMEOS_EBML_WRITER_H_
-#define MEDIA_WEBM_CHROMEOS_EBML_WRITER_H_
-
-#include "base/callback.h"
-
-// This struct serves as a bridge betweeen static libmkv interface and Chrome's
-// base::Callback. Must be in the global namespace. See EbmlWriter.h.
-struct EbmlGlobal {
-  base::Callback<void(const void* buffer, unsigned long len)> write_cb;
-  base::Callback<void(const void* buffer, int buffer_size, unsigned long len)>
-      serialize_cb;
-};
-
-#endif  // MEDIA_WEBM_CHROMEOS_EBML_WRITER_H_