media: Support unprefixed EME API on Android.

media/base/media_keys.h

 // Copyright 2013 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_BASE_MEDIA_KEYS_H_
 #define MEDIA_BASE_MEDIA_KEYS_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 43 matching lines @@
   };
 
   // Must be a superset of cdm::MediaKeyException.
   enum Exception {
     NOT_SUPPORTED_ERROR,
     INVALID_STATE_ERROR,
     INVALID_ACCESS_ERROR,
     QUOTA_EXCEEDED_ERROR,
     UNKNOWN_ERROR,
     CLIENT_ERROR,
-    OUTPUT_ERROR
+    OUTPUT_ERROR,

[ddorwin, 2015/01/14 23:09:21]

The name "exception" and inclusion of "output" is odd. I guess this is used for
legacy key error? For unprefixed, output is not an exception (not used when
rejecting a promise).

[xhwang, 2015/01/15 08:13:13]

Acknowledged.

+    EXCEPTION_MAX = OUTPUT_ERROR

[ddorwin, 2015/01/14 23:09:21]

This is painful to maintain. :(
We had a conversation about "MAX" for UMAs, but I don't know what the outcome
was for other enums.

[xhwang, 2015/01/15 08:13:13]

Agreed this is ugly. It seems most enums used in IPC use MAX_EXCEPTION style
instead of NUM_EXCEPTIONS style. Also NUM_EXCEPTIONS introduces a new enum
value. In that sense, MAX_EXCEPTION seems cleaner.

   };
 
   // Type of license required when creating/loading a session.
   // Must be consistent with the values specified in the spec:
   // https://w3c.github.io/encrypted-media/#idl-def-MediaKeySessionType
   enum SessionType {
     TEMPORARY_SESSION,
     PERSISTENT_LICENSE_SESSION,
     PERSISTENT_RELEASE_MESSAGE_SESSION
   };
 
   virtual ~MediaKeys();
 
   // Provides a server certificate to be used to encrypt messages to the
   // license server.
   virtual void SetServerCertificate(const uint8* certificate_data,
                                     int certificate_data_length,
                                     scoped_ptr<SimpleCdmPromise> promise) = 0;
 
-  // Creates a session with the |init_data_type|, |init_data| and |session_type|
-  // provided.
-  // Note: UpdateSession() and ReleaseSession() should only be called after
-  // |promise| is resolved.
+  // Creates a session with |session_type|. Then generates a request with the
+  // |init_data_type| and |init_data|.
+  // Note:
+  // 1. The session ID will be provided when the |promise| is resolved.
+  // 2. The generated request should be returned through a SessionMessageCB,
+  //    which must be AFTER the |promise| is resolved. Otherwise, the session ID
+  //    in the callback will not be recognized.
+  // 3. UpdateSession(), CloseSession() and RemoveSession() should only be
+  //    called after the |promise| is resolved.
   virtual void CreateSessionAndGenerateRequest(
       SessionType session_type,
       const std::string& init_data_type,
       const uint8* init_data,
       int init_data_length,
       scoped_ptr<NewSessionCdmPromise> promise) = 0;
 
   // Loads a session with the |web_session_id| provided.
-  // Note: UpdateSession() and ReleaseSession() should only be called after
-  // |promise| is resolved.
+  // Note: UpdateSession(), CloseSession() and RemoveSession() should only be
+  //       called after the |promise| is resolved.
   virtual void LoadSession(SessionType session_type,
                            const std::string& web_session_id,
                            scoped_ptr<NewSessionCdmPromise> promise) = 0;
 
   // Updates a session specified by |web_session_id| with |response|.
   virtual void UpdateSession(const std::string& web_session_id,
                              const uint8* response,
                              int response_length,
                              scoped_ptr<SimpleCdmPromise> promise) = 0;
 
@@ skipping 20 matching lines @@
 
 // Key event callbacks. See the spec for details:
 // https://dvcs.w3.org/hg/html-media/raw-file/default/encrypted-media/encrypted-media.html#event-summary
 typedef base::Callback<void(const std::string& web_session_id,
                             const std::vector<uint8>& message,
                             const GURL& destination_url)> SessionMessageCB;
 
 typedef base::Callback<void(const std::string& web_session_id)> SessionClosedCB;
 
 typedef base::Callback<void(const std::string& web_session_id,
-                            MediaKeys::Exception exception_code,
+                            MediaKeys::Exception exception,
                             uint32 system_code,
                             const std::string& error_message)> SessionErrorCB;
 
 typedef base::Callback<void(const std::string& web_session_id,
                             bool has_additional_usable_key,
                             CdmKeysInfo keys_info)> SessionKeysChangeCB;
 
 typedef base::Callback<void(const std::string& web_session_id,
                             const base::Time& new_expiry_time)>
     SessionExpirationUpdateCB;
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_MEDIA_KEYS_H_