Update from https://crrev.com/316786

cc/layers/video_frame_provider_client_impl.h

Index: cc/layers/video_frame_provider_client_impl.h
diff --git a/cc/layers/video_frame_provider_client_impl.h b/cc/layers/video_frame_provider_client_impl.h
index b6eb86f0fef659d4b4928cde60e416c3cb4026af..39f66fb009db00e81960b3099c243495f8f58f02 100644
--- a/cc/layers/video_frame_provider_client_impl.h
+++ b/cc/layers/video_frame_provider_client_impl.h
@@ -7,6 +7,7 @@
 
 #include "base/memory/ref_counted.h"
 #include "base/synchronization/lock.h"
+#include "base/threading/thread_checker.h"
 #include "cc/layers/video_frame_provider.h"
 #include "ui/gfx/transform.h"
 
@@ -23,12 +24,10 @@ class VideoFrameProviderClientImpl
       VideoFrameProvider* provider);
 
   VideoLayerImpl* active_video_layer() { return active_video_layer_; }
-  void set_active_video_layer(VideoLayerImpl* video_layer) {
-    active_video_layer_ = video_layer;
-  }
+  void SetActiveVideoLayer(VideoLayerImpl* video_layer);
 
   void Stop();
-  bool Stopped() const { return !provider_; }
+  bool Stopped();
 
   scoped_refptr<media::VideoFrame> AcquireLockAndCurrentFrame();
   void PutCurrentFrame(const scoped_refptr<media::VideoFrame>& frame);
@@ -53,6 +52,7 @@ class VideoFrameProviderClientImpl
   // Guards the destruction of provider_ and the frame that it provides
   base::Lock provider_lock_;
   VideoFrameProvider* provider_;
+  base::ThreadChecker thread_checker_;
 
   gfx::Transform stream_texture_matrix_;