Add Keyboard Latency UMA Metrics.

content/browser/renderer_host/render_widget_host_view_base.h

Index: content/browser/renderer_host/render_widget_host_view_base.h
diff --git a/content/browser/renderer_host/render_widget_host_view_base.h b/content/browser/renderer_host/render_widget_host_view_base.h
index 40ff13c4161da9f6bfc8fc400454297193a0fae2..b4e605579d1bda9efceb35f21fbda7bc49d78666 100644
--- a/content/browser/renderer_host/render_widget_host_view_base.h
+++ b/content/browser/renderer_host/render_widget_host_view_base.h
@@ -261,7 +261,8 @@ class CONTENT_EXPORT RenderWidgetHostViewBase : public RenderWidgetHostView,
       cc::SurfaceHittestDelegate* delegate,
       const gfx::Point& point,
       gfx::Point* transformed_point);
-  virtual void ProcessKeyboardEvent(const NativeWebKeyboardEvent& event) {}
+  virtual void ProcessKeyboardEvent(const NativeWebKeyboardEvent& event,
+                                    const ui::LatencyInfo& latency) {}
   virtual void ProcessMouseEvent(const blink::WebMouseEvent& event,
                                  const ui::LatencyInfo& latency) {}
   virtual void ProcessMouseWheelEvent(const blink::WebMouseWheelEvent& event,