Update MediaKeySession method names to latest EME spec.

public/platform/WebContentDecryptionModuleSession.h

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 40 matching lines @@
         virtual void keyError(MediaKeyErrorCode, unsigned long systemCode) = 0;
         virtual void keyMessage(const unsigned char* message, size_t messageLength, const blink::WebURL& destinationURL) = 0;
 
     protected:
         virtual ~Client();
     };
 
     virtual ~WebContentDecryptionModuleSession();
 
     virtual WebString sessionId() const = 0;
-    virtual void generateKeyRequest(const WebString& mimeType, const unsigned char* initData, size_t initDataLength) = 0;
-    virtual void update(const unsigned char* key, size_t keyLength) = 0;
-    virtual void close() = 0;
+    virtual void initialize(const WebString& mimeType, const unsigned char* initData, size_t initDataLength) = 0;
+    virtual void update(const unsigned char* response, size_t responseLength) = 0;
+    virtual void release() = 0;
 };
 
 } // namespace blink
 
 #endif // WebContentDecryptionModuleSession_h