Revert "Fix Omnibox.CharTypedToRepaintLatency regression with D3DVsync experiment"

cc/scheduler/begin_frame_source.h

Index: cc/scheduler/begin_frame_source.h
diff --git a/cc/scheduler/begin_frame_source.h b/cc/scheduler/begin_frame_source.h
index ea7276a26c88dc4a7d1650d2e429f77661ba74ac..e21878dd0470a323492b41a71b570a698fd92a1e 100644
--- a/cc/scheduler/begin_frame_source.h
+++ b/cc/scheduler/begin_frame_source.h
@@ -257,10 +257,6 @@ class CC_EXPORT ExternalBeginFrameSource : public BeginFrameSource {
   void OnBeginFrame(const BeginFrameArgs& args);
 
  protected:
-  // Called on AddObserver and gets missed BeginFrameArgs for the given
-  // observer.
-  virtual BeginFrameArgs GetMissedBeginFrameArgs(BeginFrameObserver* obs);
-
   BeginFrameArgs last_begin_frame_args_;
   std::unordered_set<BeginFrameObserver*> observers_;
   ExternalBeginFrameSourceClient* client_;