Change FrameBuffer::Stop to not require a critical section.

webrtc/modules/video_coding/frame_buffer2.h

Index: webrtc/modules/video_coding/frame_buffer2.h
diff --git a/webrtc/modules/video_coding/frame_buffer2.h b/webrtc/modules/video_coding/frame_buffer2.h
index b554f5b194c48f8af5343d465e01d48b963b8a85..87486237c9be556528c4fc6924129ee70c09fa07 100644
--- a/webrtc/modules/video_coding/frame_buffer2.h
+++ b/webrtc/modules/video_coding/frame_buffer2.h
@@ -149,7 +149,7 @@ class FrameBuffer {
 
   rtc::CriticalSection crit_;
   Clock* const clock_;
-  rtc::Event new_countinuous_frame_event_;
+  rtc::Event new_continuous_frame_event_;
   VCMJitterEstimator* const jitter_estimator_ GUARDED_BY(crit_);
   VCMTiming* const timing_ GUARDED_BY(crit_);
   VCMInterFrameDelay inter_frame_delay_ GUARDED_BY(crit_);
@@ -159,7 +159,7 @@ class FrameBuffer {
   FrameMap::iterator next_frame_it_ GUARDED_BY(crit_);
   int num_frames_history_ GUARDED_BY(crit_);
   int num_frames_buffered_ GUARDED_BY(crit_);
-  bool stopped_ GUARDED_BY(crit_);
+  volatile int stopped_;
   VCMVideoProtection protection_mode_ GUARDED_BY(crit_);
   VCMReceiveStatisticsCallback* const stats_callback_;