Bug Fix: Data Race For WebMediaPlayerMS' Frame Count Variable

content/renderer/media/webmediaplayer_ms_compositor.cc

 // Copyright 2015 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/webmediaplayer_ms_compositor.h"
 
 #include <stdint.h>
 #include <string>
 
 #include "base/command_line.h"
@@ skipping 160 matching lines @@
   base::AutoLock auto_lock(current_frame_lock_);
   return current_frame_ ? current_frame_->natural_size() : gfx::Size();
 }
 
 base::TimeDelta WebMediaPlayerMSCompositor::GetCurrentTime() {
   DCHECK(thread_checker_.CalledOnValidThread());
   base::AutoLock auto_lock(current_frame_lock_);
   return current_frame_.get() ? current_frame_->timestamp() : base::TimeDelta();
 }
 
-size_t WebMediaPlayerMSCompositor::total_frame_count() const {
+size_t WebMediaPlayerMSCompositor::total_frame_count() {
+  base::AutoLock auto_lock(current_frame_lock_);
   DVLOG(1) << __func__ << ", " << total_frame_count_;
   DCHECK(thread_checker_.CalledOnValidThread());
   return total_frame_count_;
 }
 
-size_t WebMediaPlayerMSCompositor::dropped_frame_count() const {
+size_t WebMediaPlayerMSCompositor::dropped_frame_count() {
+  base::AutoLock auto_lock(current_frame_lock_);
   DVLOG(1) << __func__ << ", " << dropped_frame_count_;
   DCHECK(thread_checker_.CalledOnValidThread());
   return dropped_frame_count_;
 }
 
 void WebMediaPlayerMSCompositor::SetVideoFrameProviderClient(
     cc::VideoFrameProvider::Client* client) {
   DCHECK(compositor_task_runner_->BelongsToCurrentThread());
   if (video_frame_provider_client_)
     video_frame_provider_client_->StopUsingProvider();
@@ skipping 254 matching lines @@
   }
 
   if (!rendering_frame_buffer_) {
     rendering_frame_buffer_.reset(new media::VideoRendererAlgorithm(
         base::Bind(&WebMediaPlayerMSCompositor::MapTimestampsToRenderTimeTicks,
                    base::Unretained(this))));
   }
 }
 
 }  // namespace content