Telemtry: hooks "chrome.gpuBenchmarking.smoothScrollBy" with java on android.

content/browser/renderer_host/basic_mouse_wheel_smooth_scroll_gesture.cc

Index: content/browser/renderer_host/basic_mouse_wheel_smooth_scroll_gesture.cc
diff --git a/content/browser/renderer_host/basic_mouse_wheel_smooth_scroll_gesture.cc b/content/browser/renderer_host/basic_mouse_wheel_smooth_scroll_gesture.cc
index af93b7ca05a3bf3971f54672cd016365f2fcd1d1..6740c448d54c75f2e8fac85ed90f97e8382a479b 100644
--- a/content/browser/renderer_host/basic_mouse_wheel_smooth_scroll_gesture.cc
+++ b/content/browser/renderer_host/basic_mouse_wheel_smooth_scroll_gesture.cc
@@ -26,21 +26,13 @@ bool BasicMouseWheelSmoothScrollGesture::ForwardInputEvents(
   if (pixels_scrolled_ >= pixels_to_scroll_)
     return false;
 
-  double positionDelta = 10;
-  if (!last_tick_time_.is_null()) {
-    RenderWidgetHostImpl* hostImpl = RenderWidgetHostImpl::From(host);
-    double desiredIntervalMs = hostImpl->SyntheticScrollMessageInterval();
-    double velocity = 10 / desiredIntervalMs;
-    double timeDelta = (now - last_tick_time_).InMillisecondsF();
-    positionDelta = velocity * timeDelta;
-  }
-
-  last_tick_time_ = now;
+  double position_delta = Tick(
+      now, RenderWidgetHostImpl::From(host)->SyntheticScrollMessageInterval());
 
   WebKit::WebMouseWheelEvent event;
   event.type = WebKit::WebInputEvent::MouseWheel;
   event.hasPreciseScrollingDeltas = 1;
-  event.deltaY = scroll_down_ ? -positionDelta : positionDelta;
+  event.deltaY = scroll_down_ ? -position_delta : position_delta;
   // TODO(vollick): find a proper way to access
   // WebCore::WheelEvent::tickMultiplier.
   event.wheelTicksY = event.deltaY / 120;