Media Remoting: Add remoting control logic for encrypted contents.

media/remoting/remoting_cdm_context.h

+// Copyright 2016 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_REMOTING_REMOTING_CDM_CONTEXT_H_
+#define MEDIA_REMOTING_REMOTING_CDM_CONTEXT_H_
+
+#include "media/base/cdm_context.h"
+
+namespace media {
+
+class RemotingCdm;
+class RemotingSourceImpl;
+
+// TODO(xjz): Merge this with erickung's implementation.
+class RemotingCdmContext : public CdmContext {
+ public:
+  explicit RemotingCdmContext(RemotingCdm* remoting_cdm);
+  ~RemotingCdmContext() override;
+
+  // If |cdm_context| is an instance of RemotingCdmContext, return a type-casted
+  // pointer to it. Otherwise, return nullptr.
+  static RemotingCdmContext* From(CdmContext* cdm_context);
+
+  RemotingSourceImpl* GetRemotingSource();
+
+  // CdmContext implementations.
+  Decryptor* GetDecryptor() override;
+  int GetCdmId() const override;
+  void* GetClassIdentifier() const override;
+
+ private:
+  RemotingCdm* const remoting_cdm_;  // Outlives this class.
+
+  DISALLOW_COPY_AND_ASSIGN(RemotingCdmContext);
+};
+
+}  // namespace media
+
+#endif  // MEDIA_REMOTING_REMOTING_CDM_CONTEXT_H_