[Chromoting] Implement DualBufferFrameConsumer

remoting/client/software_video_renderer.h

Index: remoting/client/software_video_renderer.h
diff --git a/remoting/client/software_video_renderer.h b/remoting/client/software_video_renderer.h
index 2172500b105162cadb61a680423b7841e8ffa722..2bd5993f75ffa530964e2529a0eeb7b2d555e320 100644
--- a/remoting/client/software_video_renderer.h
+++ b/remoting/client/software_video_renderer.h
@@ -44,6 +44,10 @@ class SoftwareVideoRenderer : public protocol::VideoRenderer,
   // be called on the same thread.
   explicit SoftwareVideoRenderer(protocol::FrameConsumer* consumer);
 
+  // std::unique_ptr version constructor that owns the consumer.

[Sergey Ulanov, 2016/07/20 18:39:26]

Suggest rewording: "Same as above, but takes ownership of the |consumer|."

[Yuwei, 2016/07/21 00:07:32]

Done.

+  explicit SoftwareVideoRenderer(
+      std::unique_ptr<protocol::FrameConsumer> consumer);
+
   // Deprecated constructor. TODO(yuweih): remove.
   // Constructs the renderer and initializes it immediately. Caller should not
   // call Initialize() after using this constructor.
@@ -77,7 +81,12 @@ class SoftwareVideoRenderer : public protocol::VideoRenderer,
                        const base::Closure& done);
 
   scoped_refptr<base::SingleThreadTaskRunner> decode_task_runner_;
+
+  // |owned_consumer_| and |consumer_| should refer to the same object if
+  // |owned_consumer_| is not null.
+  std::unique_ptr<protocol::FrameConsumer> owned_consumer_;
   protocol::FrameConsumer* const consumer_;
+
   protocol::FrameStatsConsumer* stats_consumer_ = nullptr;
 
   std::unique_ptr<VideoDecoder> decoder_;