Adding locking to webrtc::voe::Channel to fix race conditions

webrtc/voice_engine/voe_video_sync_impl.cc

Index: webrtc/voice_engine/voe_video_sync_impl.cc
diff --git a/webrtc/voice_engine/voe_video_sync_impl.cc b/webrtc/voice_engine/voe_video_sync_impl.cc
index f1c734764409c160f23a11357db46902f7d51bce..8896c905dcc05ddedf98fbd9eb88b172856b1848 100644
--- a/webrtc/voice_engine/voe_video_sync_impl.cc
+++ b/webrtc/voice_engine/voe_video_sync_impl.cc
@@ -218,7 +218,7 @@ int VoEVideoSyncImpl::GetLeastRequiredDelayMs(int channel) const {
                           "GetLeastRequiredDelayMs() failed to locate channel");
     return -1;
   }
-  return channel_ptr->least_required_delay_ms();
+  return channel_ptr->LeastRequiredDelayMs();
 }
 
 #endif  // #ifdef WEBRTC_VOICE_ENGINE_VIDEO_SYNC_API