Convert video capture pipline to base::TimeTicks

content/renderer/media/video_capture_impl.h

 // Copyright (c) 2012 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.
 
 // VideoCaptureImpl represents a capture device in renderer process. It provides
 // interfaces for clients to Start/Stop capture. It also communicates to clients
 // when buffer is ready, state of capture device is changed.
 
 // VideoCaptureImpl is also a delegate of VideoCaptureMessageFilter which relays
 // operation of a capture device to the browser process and receives responses
@@ skipping 44 matching lines @@
       const media::VideoCaptureParams& params) OVERRIDE;
   virtual void StopCapture(media::VideoCapture::EventHandler* handler) OVERRIDE;
   virtual bool CaptureStarted() OVERRIDE;
   virtual int CaptureFrameRate() OVERRIDE;
 
   // VideoCaptureMessageFilter::Delegate interface.
   virtual void OnBufferCreated(base::SharedMemoryHandle handle,
                                int length,
                                int buffer_id) OVERRIDE;
   virtual void OnBufferDestroyed(int buffer_id) OVERRIDE;
-  virtual void OnBufferReceived(
-      int buffer_id,
-      base::Time timestamp,
-      const media::VideoCaptureFormat& format) OVERRIDE;
+  virtual void OnBufferReceived(int buffer_id,
+                                base::TimeTicks timestamp,
+                                const media::VideoCaptureFormat& format)
+      OVERRIDE;
   virtual void OnStateChanged(VideoCaptureState state) OVERRIDE;
   virtual void OnDelegateAdded(int32 device_id) OVERRIDE;
 
   // Stop/resume delivering video frames to clients, based on flag |suspend|.
   virtual void SuspendCapture(bool suspend);
 
  private:
   friend class VideoCaptureImplManager;
   friend class VideoCaptureImplTest;
   friend class MockVideoCaptureImpl;
 
   class ClientBuffer;
   typedef std::map<media::VideoCapture::EventHandler*,
                    media::VideoCaptureParams> ClientInfo;
 
   VideoCaptureImpl(media::VideoCaptureSessionId session_id,
                    base::MessageLoopProxy* capture_message_loop_proxy,
                    VideoCaptureMessageFilter* filter);
   virtual ~VideoCaptureImpl();
 
   void DoStartCaptureOnCaptureThread(
       media::VideoCapture::EventHandler* handler,
       const media::VideoCaptureParams& params);
   void DoStopCaptureOnCaptureThread(media::VideoCapture::EventHandler* handler);
   void DoBufferCreatedOnCaptureThread(base::SharedMemoryHandle handle,
                                       int length,
                                       int buffer_id);
   void DoBufferDestroyedOnCaptureThread(int buffer_id);
-  void DoBufferReceivedOnCaptureThread(
-      int buffer_id,
-      base::Time timestamp,
-      const media::VideoCaptureFormat& format);
+  void DoBufferReceivedOnCaptureThread(int buffer_id,
+                                       base::TimeTicks timestamp,
+                                       const media::VideoCaptureFormat& format);
   void DoClientBufferFinishedOnCaptureThread(
       int buffer_id,
       const scoped_refptr<ClientBuffer>& buffer);
   void DoStateChangedOnCaptureThread(VideoCaptureState state);
   void DoDelegateAddedOnCaptureThread(int32 device_id);
 
   void DoSuspendCaptureOnCaptureThread(bool suspend);
 
   void Init();
   void DeInit(base::Closure task);
@@ skipping 23 matching lines @@
   ClientInfo clients_pending_on_filter_;
   ClientInfo clients_pending_on_restart_;
 
   // Member params_ represents the video format requested by the
   // client to this class via DoStartCaptureOnCaptureThread.
   media::VideoCaptureParams params_;
 
   // The device's video capture format sent from browser process side.
   media::VideoCaptureFormat last_frame_format_;
 
+  // The device's last captured frame timestamp sent from browser process side.
+  base::TimeTicks last_frame_timestamp_;

[miu, 2014/01/06 22:39:37]

This comment and member name are wrong.  This looks like a
"first_frame_timestamp_" instead.  No gripes with your approach here--I like
what you've done--just the naming/comment need to reflect that this is the
timestamp of the first frame and used to compute monotonically non-decreasing
frame time deltas.

[sheu, 2014/01/06 22:52:37]

Heh yeah.  I was not really paying enough attention here :-)

+
   bool suspended_;
   VideoCaptureState state_;
 
   // WeakPtrFactory pointing back to |this| object, for use with
   // media::VideoFrames constructed in OnBufferReceived() from buffers cached
   // in |client_buffers_|.
   base::WeakPtrFactory<VideoCaptureImpl> weak_this_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(VideoCaptureImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_VIDEO_CAPTURE_IMPL_H_