Add TimeToScrollUpdateSwapBegin2 in RAPPOR

content/browser/renderer_host/input/render_widget_host_latency_tracker.h

Index: content/browser/renderer_host/input/render_widget_host_latency_tracker.h
diff --git a/content/browser/renderer_host/input/render_widget_host_latency_tracker.h b/content/browser/renderer_host/input/render_widget_host_latency_tracker.h
index 1dc74f2c86cf6c788f4be33d4dd37d09104abbeb..c3cdc61922685a025da9d18950573e4e7a1831dd 100644
--- a/content/browser/renderer_host/input/render_widget_host_latency_tracker.h
+++ b/content/browser/renderer_host/input/render_widget_host_latency_tracker.h
@@ -17,11 +17,13 @@
 
 namespace content {
 
+class RenderWidgetHostImpl;
+
 // Utility class for tracking the latency of events passing through
 // a given RenderWidgetHost.
 class CONTENT_EXPORT RenderWidgetHostLatencyTracker {
  public:
-  RenderWidgetHostLatencyTracker();
+  RenderWidgetHostLatencyTracker(RenderWidgetHostImpl*);

[ncarter (slow), 2016/12/08 17:47:14]

single-arg ctor should be explicit

[Navid Zolghadr, 2016/12/09 19:13:28]

Done.

   ~RenderWidgetHostLatencyTracker();
 
   // Associates the latency tracker with a given route and process.
@@ -80,6 +82,8 @@ class CONTENT_EXPORT RenderWidgetHostLatencyTracker {
   // default action prevented. Only valid for single finger gestures.
   bool touch_start_default_prevented_;
 
+  RenderWidgetHostImpl* render_widget_host_impl;
+
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostLatencyTracker);
 };