cc: Track BeginMainFrame more precisely in CompositorTimingHistory.

cc/trees/threaded_channel.h

Index: cc/trees/threaded_channel.h
diff --git a/cc/trees/threaded_channel.h b/cc/trees/threaded_channel.h
index 50d71407f3dae3a6a181b5c4e4cbf8322545a41f..290831fd384bc819a0fd56882e751680ce807322 100644
--- a/cc/trees/threaded_channel.h
+++ b/cc/trees/threaded_channel.h
@@ -85,7 +85,9 @@ class CC_EXPORT ThreadedChannel : public ChannelMain, public ChannelImpl {
   void SetInputThrottledUntilCommitOnImpl(bool is_throttled) override;
   void SetDeferCommitsOnImpl(bool defer_commits) override;
   void SetNeedsCommitOnImpl() override;
-  void BeginMainFrameAbortedOnImpl(CommitEarlyOutReason reason) override;
+  void BeginMainFrameAbortedOnImpl(
+      CommitEarlyOutReason reason,
+      base::TimeTicks main_thread_start_time) override;
   void SetNeedsRedrawOnImpl(const gfx::Rect& damage_rect) override;
 
   // Blocking calls to ProxyImpl
@@ -96,7 +98,8 @@ class CC_EXPORT ThreadedChannel : public ChannelMain, public ChannelImpl {
   void MainFrameWillHappenOnImplForTesting(
       CompletionEvent* completion,
       bool* main_frame_will_happen) override;
-  void StartCommitOnImpl(CompletionEvent* completion) override;
+  void StartCommitOnImpl(CompletionEvent* completion,
+                         base::TimeTicks main_thread_start_time) override;
 
   // ChannelImpl Implementation
   void DidCompleteSwapBuffers() override;