Make MediaStreamVideoTrack::GetSettings return the track's frame rate.

content/renderer/media/media_stream_video_track.cc

 // Copyright 2013 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/media_stream_video_track.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/location.h"
@@ skipping 373 matching lines @@
   if (source_) {
     source_->RemoveTrack(this);
     source_ = NULL;
   }
   OnReadyStateChanged(blink::WebMediaStreamSource::kReadyStateEnded);
 }
 
 void MediaStreamVideoTrack::GetSettings(
     blink::WebMediaStreamTrack::Settings& settings) {
   DCHECK(main_render_thread_checker_.CalledOnValidThread());
+  if (!source_)
+    return;
+
   if (width_ && height_) {
     settings.width = width_;
     settings.height = height_;
   }
 
-  if (!source_)
-    return;
+  // 0.0 means the track is using the source's frame rate.
+  if (frame_rate_ != 0.0) {
+    settings.frame_rate = frame_rate_;
+  }
 
   base::Optional<media::VideoCaptureFormat> format =
       source_->GetCurrentFormat();
   if (format) {
-    settings.frame_rate = format->frame_rate;
+    if (frame_rate_ == 0.0)
+      settings.frame_rate = format->frame_rate;
     settings.video_kind = GetVideoKindForFormat(*format);
   }
   switch (source_->device_info().device.video_facing) {
     case media::MEDIA_VIDEO_FACING_NONE:
       settings.facing_mode = blink::WebMediaStreamTrack::FacingMode::kNone;
       break;
     case media::MEDIA_VIDEO_FACING_USER:
       settings.facing_mode = blink::WebMediaStreamTrack::FacingMode::kUser;
       break;
     case media::MEDIA_VIDEO_FACING_ENVIRONMENT:
@@ skipping 15 matching lines @@
 }
 
 void MediaStreamVideoTrack::OnReadyStateChanged(
     blink::WebMediaStreamSource::ReadyState state) {
   DCHECK(main_render_thread_checker_.CalledOnValidThread());
   for (auto* sink : sinks_)
     sink->OnReadyStateChanged(state);
 }
 
 }  // namespace content