Fix reporting of TouchToFirstScroll latency metrics

content/browser/renderer_host/input/render_widget_host_latency_tracker.cc

Index: content/browser/renderer_host/input/render_widget_host_latency_tracker.cc
diff --git a/content/browser/renderer_host/input/render_widget_host_latency_tracker.cc b/content/browser/renderer_host/input/render_widget_host_latency_tracker.cc
index e2ef1e441c80b81c95d5add1c22e53600cc3e2d4..3a54d028bfe8edce7bc97772fd2af6926099139b 100644
--- a/content/browser/renderer_host/input/render_widget_host_latency_tracker.cc
+++ b/content/browser/renderer_host/input/render_widget_host_latency_tracker.cc
@@ -427,6 +427,16 @@ void RenderWidgetHostLatencyTracker::OnSwapCompositorFrame(
 
 void RenderWidgetHostLatencyTracker::OnFrameSwapped(
     const LatencyInfo& latency) {
+  // Don't report frame latency on wheel events. Previously they were only
+  // reported on Touch metrics and we need to be consistent across reporting

[tdresser, 2016/04/22 17:55:59]

nit: inconsistent capitalization.

Might as well "Touch" -> "touch"

[dtapuska, 2016/04/22 18:14:59]

Done.

+  // metrics.
+  LatencyInfo::LatencyComponent mouse_wheel_scroll_update_component;
+  if (latency.FindLatency(
+          ui::INPUT_EVENT_LATENCY_GENERATE_SCROLL_UPDATE_FROM_MOUSE_WHEEL, 0,
+          &mouse_wheel_scroll_update_component)) {
+    return;
+  }
+
   LatencyInfo::LatencyComponent gpu_swap_end_component;
   if (!latency.FindLatency(
           ui::INPUT_EVENT_LATENCY_TERMINATED_FRAME_SWAP_COMPONENT, 0,