Add Decryptor interface.

media/crypto/decryptor_client.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_CRYPTO_DECRYPTOR_CLIENT_H_
-#define MEDIA_CRYPTO_DECRYPTOR_CLIENT_H_
-
-#include <string>
-
-#include "base/memory/scoped_ptr.h"
-#include "media/crypto/aes_decryptor.h"
-
-namespace media {
-
-// Interface used by a decryptor to fire key events.
-// See: http://dvcs.w3.org/hg/html-media/raw-file/tip/encrypted-media/encrypted-media.html#event-summary
-class DecryptorClient {
- public:
-  // Signals that a key has been added.
-  virtual void KeyAdded(const std::string& key_system,
-                        const std::string& session_id) = 0;
-
-  // Signals that a key error occurred. The |system_code| is key
-  // system-dependent. For clear key system, the |system_code| is always zero.
-  virtual void KeyError(const std::string& key_system,
-                        const std::string& session_id,
-                        AesDecryptor::KeyError error_code,
-                        int system_code) = 0;
-
-  // Signals that a key message has been generated.
-  virtual void KeyMessage(const std::string& key_system,
-                          const std::string& session_id,
-                          scoped_array<uint8> message,
-                          int message_length,
-                          const std::string& default_url) = 0;
-
-  // Signals that a key is needed for decryption. |key_system| and |session_id|
-  // can be empty if the key system has not been selected.
-  virtual void NeedKey(const std::string& key_system,
-                       const std::string& session_id,
-                       scoped_array<uint8> init_data,
-                       int init_data_length) = 0;
-
- protected:
-  virtual ~DecryptorClient() {}
-};
-
-}  // namespace media
-
-#endif  // MEDIA_CRYPTO_DECRYPTOR_CLIENT_H_