Media Remoting: Add remoting control logic for encrypted contents.

media/base/cdm_context.h

 // 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.
 
 #ifndef MEDIA_BASE_CDM_CONTEXT_H_
 #define MEDIA_BASE_CDM_CONTEXT_H_
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "media/base/media_export.h"
@@ skipping 16 matching lines @@
   // CDM does not support a Decryptor (i.e. platform-based CDMs where decryption
   // occurs implicitly along with decoding). The returned object is only
   // guaranteed to be valid during the CDM's lifetime.
   virtual Decryptor* GetDecryptor() = 0;
 
   // Returns an ID that can be used to find a remote CDM, in which case this CDM
   // serves as a proxy to the remote one. Returns kInvalidCdmId when remote CDM
   // is not supported (e.g. this CDM is a local CDM).
   virtual int GetCdmId() const = 0;
 
+  // Returns a unique class identifier. Some subclasses override and use this
+  // method to provide safe down-casting to their type.
+  virtual void* GetClassIdentifier() const;
+
  protected:
   CdmContext();
 
  private:
   DISALLOW_COPY_AND_ASSIGN(CdmContext);
 };
 
 // Callback to notify that the CdmContext has been completely attached to
 // the media pipeline. Parameter indicates whether the operation succeeded.
 typedef base::Callback<void(bool)> CdmAttachedCB;
 
 // A dummy implementation of CdmAttachedCB.
 MEDIA_EXPORT void IgnoreCdmAttached(bool success);
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_CDM_CONTEXT_H_