Add Mojo CDM Service.

media/mojo/interfaces/content_decryption_module.mojom

+// Copyright 2014 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.
+
+module mojo;

[jamesr, 2014/12/02 22:25:59]

shouldn't this be in a media module? or perhaps something more focused?

[xhwang, 2014/12/03 01:23:42]

The MediaRenderer interface is in mojo module and I was following that.

"media" module makes sense. But that'll put a lot of stuff in media namespace
and we'll have a lot of naming conflicts. Or I'll need to find a new name for
each struct/class, which is painful.

Another option is to have a media.mojo module, which will be translated to
media::mojo namespace.

WDYT?

+
+import "media/mojo/interfaces/decryptor.mojom";
+
+enum CdmException {
+  NOT_SUPPORTED_ERROR,
+  INVALID_STATE_ERROR,
+  INVALID_ACCESS_ERROR,
+  QUOTA_EXCEEDED_ERROR,
+  UNKNOWN_ERROR,
+  CLIENT_ERROR,
+  OUTPUT_ERROR
+};
+
+struct CdmContext {
+  Decryptor? decryptor;

[jamesr, 2014/12/02 22:25:59]

can you add some comments to these guys? what does it mean for the decryptor to
be null?

[xhwang, 2014/12/03 01:23:42]

Done.

+  int32 cdm_id;
+};
+
+struct CdmPromiseResult {
+  bool success;
+  CdmException exception_code;
+  uint32 system_code;
+  string error_message;
+};
+
+[Client=ContentDecryptionModuleClient]
+interface ContentDecryptionModule {
+  enum SessionType {
+    TEMPORARY_SESSION,
+    PERSISTENT_SESSION
+  };
+
+  // Provides a server certificate to be used to encrypt messages to the
+  // license server.
+  SetServerCertificate(array<uint8> certificate_data)
+      => (CdmPromiseResult result);
+
+  // Creates a session with the |init_data_type|, |init_data| and |session_type|
+  // provided.
+  CreateSession(string init_data_type,
+                array<uint8> init_data,
+                SessionType session_type)
+      => (CdmPromiseResult result, string? session_id);
+
+  // Loads a session with the |session_id| provided.
+  LoadSession(string session_id)
+      => (CdmPromiseResult result, string? session_id);

[jamesr, 2014/12/02 22:25:59]

what does it mean for session_id to be null?

[xhwang, 2014/12/03 01:23:42]

Done.

+
+  // Updates a session specified by |session_id| with |response|.
+  UpdateSession(string session_id, array<uint8> response)
+      => (CdmPromiseResult result);
+
+  // Closes the session specified by |session_id|.
+  CloseSession(string session_id) => (CdmPromiseResult result);
+
+  // Removes stored session data associated with the session specified by
+  // |session_id|.
+  RemoveSession(string session_id) => (CdmPromiseResult result);
+
+  // Retrieves the key IDs for keys in the session that the CDM knows are
+  // currently usable to decrypt media data.
+  GetUsableKeyIds(string session_id)
+      => (CdmPromiseResult result, array<array<uint8>>? usable_key_ids);
+  
+  // Retrieves the CdmContext associated with this CDM instance.
+  GetCdmContext(CdmContext& cdm_context);
+};
+
+interface ContentDecryptionModuleClient {
+  OnSessionMessage(string session_id, array<uint8> message,
+                   string destination_url);
+
+  OnSessionReady(string session_id);
+
+  OnSessionClosed(string session_id);
+
+  OnSessionError(string session_id, CdmException exception_code,
+                 uint32 system_code, string error_message);
+
+  OnSessionKeysChange(string session_id, bool has_additional_usable_key);
+
+  OnSessionExpirationUpdate(string session_id, int64 new_expiry_time_usec);
+};