cc: Track BeginMainFrame more precisely in CompositorTimingHistory.

cc/trees/thread_proxy.h

Index: cc/trees/thread_proxy.h
diff --git a/cc/trees/thread_proxy.h b/cc/trees/thread_proxy.h
index c3f3f2f9a64106c6ba2863757b951eb8b7b8e791..3aaef46f01536e1b6adf1e2f02be912838fcfd50 100644
--- a/cc/trees/thread_proxy.h
+++ b/cc/trees/thread_proxy.h
@@ -291,8 +291,11 @@ class CC_EXPORT ThreadProxy : public Proxy,
       bool* main_frame_will_happen) override;
   void SetNeedsCommitOnImpl() override;
   void SetNeedsRedrawOnImpl(const gfx::Rect& damage_rect) override;
-  void BeginMainFrameAbortedOnImpl(CommitEarlyOutReason reason) override;
-  void StartCommitOnImpl(CompletionEvent* completion) override;
+  void BeginMainFrameAbortedOnImpl(
+      CommitEarlyOutReason reason,
+      base::TimeTicks main_thread_start_time) override;
+  void StartCommitOnImpl(CompletionEvent* completion,
+                         base::TimeTicks main_thread_start_time) override;
 
   // Returns |true| if the request was actually sent, |false| if one was
   // already outstanding.