Update WebContentDecryptionModuleSessionImpl to the latest EME spec.

content/renderer/media/webcontentdecryptionmodulesession_impl.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 CONTENT_RENDERER_MEDIA_WEBCONTENTDECRYPTIONMODULESESSION_IMPL_H_
 #define CONTENT_RENDERER_MEDIA_WEBCONTENTDECRYPTIONMODULESESSION_IMPL_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 16 matching lines @@
 
   WebContentDecryptionModuleSessionImpl(
       uint32 session_id,
       media::MediaKeys* media_keys,
       Client* client,
       const SessionClosedCB& session_closed_cb);
   virtual ~WebContentDecryptionModuleSessionImpl();
 
   // blink::WebContentDecryptionModuleSession implementation.
   virtual blink::WebString sessionId() const;
+  virtual void initialize(const blink::WebString& mime_type,

[ddorwin, 2014/01/07 01:17:59]

I don't think "initialize" is a good long term name.

If a session object was created with loadSession(), initialize() wouldn't make
sense. In that scenario, GKR() is more accurate.

Also, the spec now says to "Process type and initData" because there is no
guarantee that a request will be generated.

I don't have any suggestions better than processInitData(). I had a hard time
with the spec language too.

[xhwang, 2014/01/07 01:38:25]

I like "initialize" because it's generic and can be interpreted as needed
(similar to "update"). I agree GKR is more accurate about what we do, but in
chromium implementation we also generate the session ID in this call. So GKR
doesn't cover all what we do.

Also, I feel "init"ialize("init"_data) matches pretty well. But this is not
important :)

For loadSession, the proposal is loadSession(DOMString sessionId), which doesn't
pass in a init data, so "initialize" or "GKR" won't be called in this class.

In summary, I like "initialize" better, but I am okay with GKR or other names if
you prefer :)

[ddorwin, 2014/01/07 02:41:37]

Maybe something like finishCreation but better. If you think about the scenario
where we have a load() method here, the session has already been "created" and
load is finishing the work of loadSession(). The two methods should be similar.

I think the problem becomes more apparent when you look at the Blink side where
we have initializeTimer. What does the timer do? Would we have two separate
timers? If so, how would they be identified?

[ddorwin, 2014/01/07 02:41:37]

The problem with "initialize" is that something should always be initialized but
it doesn't apply to loadSession().

If you think about the scenario where we have a load() method here, the session
has already been "created" and load is finishing the work of loadSession(). The
two methods should be similar.

Maybe something like finishNewSessionCreation() or initializeCreatedSession()
but better. 

I also think the problem becomes more apparent when you look at the Blink side
where we have initializeTimer. What does the timer do? Would we have two
separate timers? If so, how would they be identified?

+                          const uint8* init_data,
+                          size_t init_data_length);
+  virtual void update(const uint8* response, size_t response_length);
+  virtual void release();
+
+  // TODO(xhwang): Drop generateKeyRequest() and close() after blink side is
+  // updated.
   virtual void generateKeyRequest(const blink::WebString& mime_type,
                                   const uint8* init_data,
                                   size_t init_data_length);
-  virtual void update(const uint8* response, size_t response_length);
   virtual void close();
 
   // Callbacks.
   void OnSessionCreated(const std::string& web_session_id);
   void OnSessionMessage(const std::vector<uint8>& message,
                         const std::string& destination_url);
   void OnSessionReady();
   void OnSessionClosed();
   void OnSessionError(media::MediaKeys::KeyError error_code, int system_code);
 
@@ skipping 11 matching lines @@
   // Session ID is used to uniquely track this object so that CDM callbacks
   // can get routed to the correct object.
   const uint32 session_id_;
 
   DISALLOW_COPY_AND_ASSIGN(WebContentDecryptionModuleSessionImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_WEBCONTENTDECRYPTIONMODULESESSION_IMPL_H_