Remove media::VideoRenderer::SetPlaybackRate().

media/filters/video_renderer_impl.cc

Index: media/filters/video_renderer_impl.cc
diff --git a/media/filters/video_renderer_impl.cc b/media/filters/video_renderer_impl.cc
index 8735a0a96f2ae2ec6424c453673495e9e163fd51..49855c74af612495a679514c09eefe9da1346734 100644
--- a/media/filters/video_renderer_impl.cc
+++ b/media/filters/video_renderer_impl.cc
@@ -34,7 +34,6 @@ VideoRendererImpl::VideoRendererImpl(
       thread_(),
       pending_read_(false),
       drop_frames_(drop_frames),
-      playback_rate_(0),
       buffering_state_(BUFFERING_HAVE_NOTHING),
       paint_cb_(paint_cb),
       last_timestamp_(kNoTimestamp()),
@@ -106,12 +105,6 @@ void VideoRendererImpl::Stop(const base::Closure& callback) {
   video_frame_stream_.Stop(callback);
 }
 
-void VideoRendererImpl::SetPlaybackRate(float playback_rate) {
-  DCHECK(task_runner_->BelongsToCurrentThread());
-  base::AutoLock auto_lock(lock_);
-  playback_rate_ = playback_rate;
-}
-
 void VideoRendererImpl::StartPlayingFrom(base::TimeDelta timestamp) {
   DCHECK(task_runner_->BelongsToCurrentThread());
   base::AutoLock auto_lock(lock_);
@@ -221,8 +214,7 @@ void VideoRendererImpl::ThreadMain() {
       return;
 
     // Remain idle as long as we're not playing.
-    if (state_ != kPlaying || playback_rate_ == 0 ||
-        buffering_state_ != BUFFERING_HAVE_ENOUGH) {
+    if (state_ != kPlaying || buffering_state_ != BUFFERING_HAVE_ENOUGH) {
       UpdateStatsAndWait_Locked(kIdleTimeDelta);
       continue;
     }
@@ -238,16 +230,9 @@ void VideoRendererImpl::ThreadMain() {
       continue;
     }
 
-    base::TimeDelta remaining_time =
-        CalculateSleepDuration(ready_frames_.front(), playback_rate_);
-
-    // Sleep up to a maximum of our idle time until we're within the time to
-    // render the next frame.
-    if (remaining_time.InMicroseconds() > 0) {
-      remaining_time = std::min(remaining_time, kIdleTimeDelta);
-      UpdateStatsAndWait_Locked(remaining_time);
-      continue;
-    }
+    base::TimeDelta now = get_time_cb_.Run();
+    base::TimeDelta earliest_paint_timestamp;
+    base::TimeDelta latest_paint_timestamp;
 
     // Deadline is defined as the midpoint between this frame and the next
     // frame, using the delta between this frame and the previous frame as the
@@ -260,15 +245,27 @@ void VideoRendererImpl::ThreadMain() {
     //
     // TODO(scherkus): This can be vastly improved. Use a histogram to measure
     // the accuracy of our frame timing code. http://crbug.com/149829
-    if (drop_frames_ && last_timestamp_ != kNoTimestamp()) {
-      base::TimeDelta now = get_time_cb_.Run();
-      base::TimeDelta deadline = ready_frames_.front()->timestamp() +
-          (ready_frames_.front()->timestamp() - last_timestamp_) / 2;
-
-      if (now > deadline) {
-        DropNextReadyFrame_Locked();
-        continue;
-      }
+    if (last_timestamp_ == kNoTimestamp()) {
+      earliest_paint_timestamp = ready_frames_.front()->timestamp();
+      latest_paint_timestamp = base::TimeDelta::Max();
+    } else {
+      base::TimeDelta duration =
+          ready_frames_.front()->timestamp() - last_timestamp_;

[xhwang, 2014/07/11 20:49:49]

nit: ready_frames_.front()->timestamp() is used 4 times. how about assigning it
to a local var/ref?

[scherkus (not reviewing), 2014/07/11 20:54:02]

Done.

+      earliest_paint_timestamp =
+          ready_frames_.front()->timestamp() - duration / 2;
+      latest_paint_timestamp =
+          ready_frames_.front()->timestamp() + duration / 2;
+    }
+
+    // Remain idle until we've reached our target paint window.
+    if (now < earliest_paint_timestamp) {
+      UpdateStatsAndWait_Locked(kIdleTimeDelta);
+      continue;
+    }
+
+    if (now > latest_paint_timestamp && drop_frames_) {
+      DropNextReadyFrame_Locked();
+      continue;
     }
 
     // Congratulations! You've made it past the video frame timing gauntlet.
@@ -477,19 +474,6 @@ void VideoRendererImpl::OnVideoFrameStreamResetDone() {
   base::ResetAndReturn(&flush_cb_).Run();
 }
 
-base::TimeDelta VideoRendererImpl::CalculateSleepDuration(
-    const scoped_refptr<VideoFrame>& next_frame,
-    float playback_rate) {
-  // Determine the current and next presentation timestamps.
-  base::TimeDelta now = get_time_cb_.Run();
-  base::TimeDelta next_pts = next_frame->timestamp();
-
-  // Scale our sleep based on the playback rate.
-  base::TimeDelta sleep = next_pts - now;
-  return base::TimeDelta::FromMicroseconds(
-      static_cast<int64>(sleep.InMicroseconds() / playback_rate));
-}
-
 void VideoRendererImpl::DoStopOrError_Locked() {
   lock_.AssertAcquired();
   last_timestamp_ = kNoTimestamp();