Add ProxyDecryptor which wraps concrete Decryptor implementations.

webkit/media/key_systems.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 WEBKIT_MEDIA_KEY_SYSTEMS_H_
-#define WEBKIT_MEDIA_KEY_SYSTEMS_H_
-
-#include <string>
-#include <vector>
-
-namespace WebKit {
-class WebString;
-}
-
-namespace webkit_media {
-
-// Returns whether |key_sytem| is supported at all.
-// Call IsSupportedKeySystemWithMediaMimeType() to determine whether a
-// |key_system| supports a specific type of media.
-bool IsSupportedKeySystem(const WebKit::WebString& key_system);
-
-// Returns whether |key_sytem| supports the specified media type and codec(s).
-bool IsSupportedKeySystemWithMediaMimeType(
-    const std::string& mime_type,
-    const std::vector<std::string>& codecs,
-    const std::string& key_system);
-
-}  // namespace webkit_media
-
-#endif  // WEBKIT_MEDIA_KEY_SYSTEMS_H_