Generalize AesDecryptor to make it more spec compliant.

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_