Convert video capture pipline to base::TimeTicks

content/renderer/media/video_capture_impl.cc

 // 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.
 
 #include "content/renderer/media/video_capture_impl.h"
 
 #include "base/bind.h"
 #include "base/stl_util.h"
 #include "content/child/child_process.h"
 #include "content/common/media/video_capture_messages.h"
@@ skipping 86 matching lines @@
 }
 
 void VideoCaptureImpl::OnBufferDestroyed(int buffer_id) {
   capture_message_loop_proxy_->PostTask(FROM_HERE,
       base::Bind(&VideoCaptureImpl::DoBufferDestroyedOnCaptureThread,
                  base::Unretained(this), buffer_id));
 }
 
 void VideoCaptureImpl::OnBufferReceived(
     int buffer_id,
-    base::Time timestamp,
+    base::TimeTicks timestamp,
     const media::VideoCaptureFormat& format) {
   capture_message_loop_proxy_->PostTask(FROM_HERE,
       base::Bind(&VideoCaptureImpl::DoBufferReceivedOnCaptureThread,
                  base::Unretained(this), buffer_id, timestamp, format));
 }
 
 void VideoCaptureImpl::OnStateChanged(VideoCaptureState state) {
   capture_message_loop_proxy_->PostTask(FROM_HERE,
       base::Bind(&VideoCaptureImpl::DoStateChangedOnCaptureThread,
                  base::Unretained(this), state));
@@ skipping 52 matching lines @@
       clients_[handler] = params;
       DCHECK_EQ(1ul, clients_.size());
       params_ = params;
       if (params_.requested_format.frame_rate >
           media::limits::kMaxFramesPerSecond) {
         params_.requested_format.frame_rate =
             media::limits::kMaxFramesPerSecond;
       }
       DVLOG(1) << "StartCapture: starting with first resolution "
                << params_.requested_format.frame_size.ToString();
-
+      last_frame_timestamp_ = base::TimeTicks();
       StartCaptureInternal();
     }
   }
 }
 
 void VideoCaptureImpl::DoStopCaptureOnCaptureThread(
     media::VideoCapture::EventHandler* handler) {
   DCHECK(capture_message_loop_proxy_->BelongsToCurrentThread());
 
   // A handler can be in only one client list.
@@ skipping 44 matching lines @@
   if (iter == client_buffers_.end())
     return;
 
   DCHECK(!iter->second || iter->second->HasOneRef())
       << "Instructed to delete buffer we are still using.";
   client_buffers_.erase(iter);
 }
 
 void VideoCaptureImpl::DoBufferReceivedOnCaptureThread(
     int buffer_id,
-    base::Time timestamp,
+    base::TimeTicks timestamp,
     const media::VideoCaptureFormat& format) {
   DCHECK(capture_message_loop_proxy_->BelongsToCurrentThread());
 
   if (state_ != VIDEO_CAPTURE_STATE_STARTED || suspended_) {
     Send(new VideoCaptureHostMsg_BufferReady(device_id_, buffer_id));
     return;
   }
 
   last_frame_format_ = format;
+  if (last_frame_timestamp_.is_null())
+    last_frame_timestamp_ = timestamp;
 
   ClientBufferMap::iterator iter = client_buffers_.find(buffer_id);
   DCHECK(iter != client_buffers_.end());
   scoped_refptr<ClientBuffer> buffer = iter->second;
   scoped_refptr<media::VideoFrame> frame =
       media::VideoFrame::WrapExternalPackedMemory(
           media::VideoFrame::I420,
           last_frame_format_.frame_size,
           gfx::Rect(last_frame_format_.frame_size),
           last_frame_format_.frame_size,
           reinterpret_cast<uint8*>(buffer->buffer->memory()),
           buffer->buffer_size,
           buffer->buffer->handle(),
-          // TODO(sheu): convert VideoCaptureMessageFilter::Delegate to use
-          // base::TimeTicks instead of base::Time.  http://crbug.com/249215
-          timestamp - base::Time::UnixEpoch(),
+          timestamp - last_frame_timestamp_,

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

Nice and clean!  :-)  I like how the first frame has a TimeDelta value of zero,
and then is monotonically non-decreasing from there.

           media::BindToLoop(
               capture_message_loop_proxy_,
               base::Bind(
                   &VideoCaptureImpl::DoClientBufferFinishedOnCaptureThread,
                   weak_this_factory_.GetWeakPtr(),
                   buffer_id,
                   buffer)));
 
   for (ClientInfo::iterator it = clients_.begin(); it != clients_.end(); ++it)
     it->first->OnFrameReady(this, frame);
@@ skipping 141 matching lines @@
   if (it != clients->end()) {
     handler->OnStopped(this);
     handler->OnRemoved(this);
     clients->erase(it);
     found = true;
   }
   return found;
 }
 
 }  // namespace content