media: Add MediaDrmBridgeCdmContext.

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 <stdint.h>
 
 #include <string>
@@ skipping 126 matching lines @@
   // the session is closed. Once the session is closed, a SessionClosedCB must
   // also be called.
   virtual void CloseSession(const std::string& session_id,
                             scoped_ptr<SimpleCdmPromise> promise) = 0;
 
   // Removes stored session data associated with the session specified by
   // |session_id|.
   virtual void RemoveSession(const std::string& session_id,
                              scoped_ptr<SimpleCdmPromise> promise) = 0;
 
-  // Returns the CdmContext associated with |this| if Decryptor or CDM ID is
-  // supported. The returned CdmContext is owned by |this|. Caller needs to make
-  // sure it is not used after |this| is destructed.
-  // Returns null if no Decryptor nor CDM ID is supported. Instead the media
-  // player may use the CDM via some platform specific method.
+  // Returns the CdmContext associated with |this|. The returned CdmContext is
+  // owned by |this| and the caller needs to make sure it is not used after
+  // |this| is destructed.
+  // Returns null if CdmContext is not supported. Instead the media player may
+  // use the CDM via some platform specific method.
   // By default this method returns null.
   // TODO(xhwang): Convert all SetCdm() implementations to use CdmContext so
   // that this function should never return nullptr.
   virtual CdmContext* GetCdmContext();
 
   // Deletes |this| on the correct thread. By default |this| is deleted
   // immediately. Override this method if |this| needs to be deleted on a
   // specific thread.
   virtual void DeleteOnCorrectThread() const;
 
@@ skipping 45 matching lines @@
 
 // Called when the CDM changes the expiration time of a session.
 // See http://w3c.github.io/encrypted-media/#update-expiration
 typedef base::Callback<void(const std::string& session_id,
                             const base::Time& new_expiry_time)>
     SessionExpirationUpdateCB;
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_MEDIA_KEYS_H_