Media Remoting: Add remoting control logic for encrypted contents.

media/remoting/remoting_sink_observer.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_SINK_OBSERVER_H_
+#define MEDIA_REMOTING_REMOTING_SINK_OBSERVER_H_
+
+#include "media/mojo/interfaces/remoting.mojom.h"
+#include "mojo/public/cpp/bindings/binding.h"
+
+namespace media {
+
+// This calss is a pure observer of remoting sink availability to indicate
+// whether a remoting session can be started.
+class RemotingSinkObserver final : public mojom::RemotingSource {
+ public:
+  RemotingSinkObserver(mojom::RemotingSourceRequest source_request,
+                       mojom::RemoterPtr remoter);
+  ~RemotingSinkObserver() override;
+
+  // RemotingSource implementations.
+  void OnSinkAvailable() override;
+  void OnSinkGone() override;
+  void OnStarted() override {}
+  void OnStartFailed(mojom::RemotingStartFailReason reason) override {}
+  void OnMessageFromSink(const std::vector<uint8_t>& message) override {}
+  void OnStopped(mojom::RemotingStopReason reason) override {}
+
+  bool is_sink_available() { return is_sink_available_; }
+
+ private:
+  const mojo::Binding<mojom::RemotingSource> binding_;
+  const mojom::RemoterPtr remoter_;
+  bool is_sink_available_ = false;
+
+  DISALLOW_COPY_AND_ASSIGN(RemotingSinkObserver);
+};
+
+}  // namespace media
+
+#endif  // MEDIA_REMOTING_REMOTING_SINK_OBSERVER_H_