Update CDM interface and add clear key CDM.

webkit/media/crypto/clear_key_cdm.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_CRYPTO_CLEAR_KEY_CDM_H_
+#define WEBKIT_MEDIA_CRYPTO_CLEAR_KEY_CDM_H_
+
+#include <string>
+
+#include "base/basictypes.h"
+#include "base/compiler_specific.h"
+#include "base/memory/ref_counted.h"
+#include "media/base/decryptor_client.h"
+#include "media/crypto/aes_decryptor.h"
+#include "webkit/media/crypto/content_decryption_module.h"
+
+namespace media {
+class DecoderBuffer;
+}
+
+class ClearKeyCdm : public ContentDecryptionModule {
+ public:
+  ClearKeyCdm();
+  virtual ~ClearKeyCdm();
+
+  // Reset the |decryption_status_| and |decrypted_buffer|.

[ddorwin, 2012/08/15 20:15:00]

Why would we need to do this? Who is calling it if it's not part of the
inherited interface?
(I see now, but it's weird.)

+  void Reset();
+
+  // ContentDecryptionModule implementation.
+  virtual CdmStatus GenerateKeyRequest(const uint8_t* init_data,
+                                       int init_data_size,
+                                       char** session_id,
+                                       int* session_id_size,
+                                       uint8_t** key_request,
+                                       int* key_request_size,
+                                       char** default_url,
+                                       int* default_url_size) OVERRIDE;

[Tom Finegan, 2012/08/15 20:02:42]

Do we want to wrap all of these up in a struct?

[xhwang, 2012/08/16 02:32:40]

This probably will change as the spec changes. I'd keep it as is for now.

+
+  virtual CdmStatus AddKey(const char* session_id,
+                           int session_id_size,
+                           const uint8_t* key,
+                           int key_size) OVERRIDE;
+
+  virtual CdmStatus CancelKeyRequest(const char* session_id,
+                                     int session_id_size) OVERRIDE;

[Tom Finegan, 2012/08/15 20:02:42]

Is the size param necessary? I think we can probably guarantee that the session
ID is NUL terminated.

[xhwang, 2012/08/16 02:32:40]

Good point. I use size here to be consistent with other code. As mentioned
earlier, the spec may change, so I'll just keep it as is.

+
+  virtual CdmStatus Decrypt(const char* session_id,
+                            int session_id_size,

[Tom Finegan, 2012/08/15 20:02:42]

Ditto.

+                            const InputBuffer& encrypted_buffer,

[ddorwin, 2012/08/15 20:15:00]

I now realize that InputBuffer is in the global namespace. Maybe we should call
it CdmInputBuffer or something to avoid conflicts. Thoughts?

[xhwang, 2012/08/16 02:32:40]

Put it in cdm namespace.

+                            OutputBuffer* decrypted_buffer) OVERRIDE;
+
+ private:
+  class Client : public media::DecryptorClient {
+   public:
+    enum Status {
+      kKeyAdded,
+      kKeyError,
+      kKeyMessage,
+      kNeedKey
+    };
+
+    Client();
+    virtual ~Client();
+
+    Status status() { return status_; }
+    const std::string& session_id() { return session_id_; }
+    const uint8* key_message() { return key_message_.get(); }
+    int key_message_length() { return key_message_length_; }
+    const std::string& default_url() { return default_url_; }
+
+    // Resets the Client to a clean state.
+    void Reset();
+
+    // media::DecryptorClient implementation.
+    virtual void KeyAdded(const std::string& key_system,
+                          const std::string& session_id) OVERRIDE;
+    virtual void KeyError(const std::string& key_system,
+                          const std::string& session_id,
+                          media::Decryptor::KeyError error_code,
+                          int system_code) OVERRIDE;
+    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) OVERRIDE;
+    virtual void NeedKey(const std::string& key_system,
+                         const std::string& session_id,
+                         scoped_array<uint8> init_data,
+                         int init_data_length) OVERRIDE;
+
+   private:
+    Status status_;
+    std::string session_id_;
+    scoped_array<uint8> key_message_;
+    int key_message_length_;
+    std::string default_url_;
+  };
+
+  // Callback that is passed in decryptor_->Decrypt().
+  void OnBufferDecrpted(media::Decryptor::Status status,

[Tom Finegan, 2012/08/15 20:02:42]

s/Decrpted/Decrypted/

[xhwang, 2012/08/16 02:32:40]

Done.

+                        const scoped_refptr<media::DecoderBuffer>& buffer);
+
+  Client client_;
+  media::AesDecryptor decryptor_;
+  media::Decryptor::Status decryption_status_;

[ddorwin, 2012/08/15 20:15:00]

I wonder why these two are members instead of transient. We should not have any
state related to decryption or we will not be able to parallelize, for example,
audio and video.

[xhwang, 2012/08/16 02:32:40]

Done.

+  scoped_refptr<media::DecoderBuffer> decrypted_buffer_;
+};
+
+#endif  // WEBKIT_MEDIA_CRYPTO_CLEAR_KEY_CDM_H_