Change VideoTrackAdapter to not drop frames if the source frame rate is known.

Also change remote video and pepper plugin MediaStreamVideoSource implementations to not set a guessed frame rate.

BUG= 394315

Review URL: https://codereview.chromium.org/517973002

Cr-Commit-Position: refs/heads/master@{#292800}

content/renderer/media/media_stream_video_source.cc

@@ -43,6 +43,7 @@ const char* kSupportedConstraints[] = {
 const int MediaStreamVideoSource::kDefaultWidth = 640;
 const int MediaStreamVideoSource::kDefaultHeight = 480;
 const int MediaStreamVideoSource::kDefaultFrameRate = 30;
+const int MediaStreamVideoSource::kUnknownFrameRate = 0;
 
 namespace {
 

content/renderer/media/media_stream_video_source.h

@@ -81,6 +81,7 @@ class CONTENT_EXPORT MediaStreamVideoSource
   static const int kDefaultWidth;
   static const int kDefaultHeight;
   static const int kDefaultFrameRate;
+  static const int kUnknownFrameRate;
 
  protected:
   virtual void DoStopSource() OVERRIDE;

content/renderer/media/video_track_adapter.cc

@@ -89,7 +89,8 @@ class VideoTrackAdapter::VideoFrameResolutionAdapter
 
   // Returns |true| if the input frame rate is higher that the requested max
   // frame rate and |frame| should be dropped.
-  bool MaybeDropFrame(const scoped_refptr<media::VideoFrame>& frame);
+  bool MaybeDropFrame(const scoped_refptr<media::VideoFrame>& frame,
+                      float source_frame_rate);
 
   // Bound to the IO-thread.
   base::ThreadChecker io_thread_checker_;
@@ -152,7 +153,7 @@ void VideoTrackAdapter::VideoFrameResolutionAdapter::DeliverFrame(
     const base::TimeTicks& estimated_capture_time) {
   DCHECK(io_thread_checker_.CalledOnValidThread());
 
-  if (MaybeDropFrame(frame))
+  if (MaybeDropFrame(frame, format.frame_rate))
     return;
 
   // TODO(perkj): Allow cropping / scaling of textures once
@@ -224,8 +225,15 @@ void VideoTrackAdapter::VideoFrameResolutionAdapter::DeliverFrame(
 }
 
 bool VideoTrackAdapter::VideoFrameResolutionAdapter::MaybeDropFrame(
-    const scoped_refptr<media::VideoFrame>& frame) {
-  if (max_frame_rate_ == 0.0f)
+    const scoped_refptr<media::VideoFrame>& frame,
+    float source_frame_rate) {
+  DCHECK(io_thread_checker_.CalledOnValidThread());
+
+  // Do not drop frames if max frame rate hasn't been specified or the source
+  // frame rate is known and is lower than max.
+  if (max_frame_rate_ == 0.0f ||
+      (source_frame_rate > 0 &&
+          source_frame_rate <= max_frame_rate_))
     return false;
 
   base::TimeDelta delta = frame->timestamp() - last_time_stamp_;
@@ -243,7 +251,7 @@ bool VideoTrackAdapter::VideoFrameResolutionAdapter::MaybeDropFrame(
     return true;
   }
   last_time_stamp_ = frame->timestamp();
-  if (delta == last_time_stamp_) // First received frame.
+  if (delta == last_time_stamp_)  // First received frame.
     return false;
   // Calculate the frame rate using a simple AR filter.
   // Use a simple filter with 0.1 weight of the current sample.

content/renderer/media/webrtc/media_stream_remote_video_source.cc

@@ -106,7 +106,7 @@ RemoteVideoSourceDelegate::RenderFrame(
   media::VideoCaptureFormat format(
       gfx::Size(video_frame->natural_size().width(),
                 video_frame->natural_size().height()),
-                MediaStreamVideoSource::kDefaultFrameRate,
+                MediaStreamVideoSource::kUnknownFrameRate,
                 pixel_format);
 
   io_message_loop_->PostTask(

content/renderer/media/webrtc/video_destination_handler.cc

@@ -146,7 +146,7 @@ void PpFrameWriter::PutFrame(PPB_ImageData_Impl* image_data,
                               gfx::Rect(frame_size), frame_size, timestamp);
   media::VideoCaptureFormat format(
       frame_size,
-      MediaStreamVideoSource::kDefaultFrameRate,
+      MediaStreamVideoSource::kUnknownFrameRate,
       media::PIXEL_FORMAT_YV12);
 
   libyuv::BGRAToI420(reinterpret_cast<uint8*>(bitmap->getPixels()),