Added missing MainThreadScrollingReason in histograms.xml

ui/events/blink/input_handler_proxy.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_EVENTS_BLINK_INPUT_HANDLER_PROXY_H_
 #define UI_EVENTS_BLINK_INPUT_HANDLER_PROXY_H_
 
 #include "base/containers/hash_tables.h"
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 71 matching lines @@
       const gfx::ScrollOffset& root_offset) override;
 
   // blink::WebGestureCurveTarget implementation.
   bool scrollBy(const blink::WebFloatSize& offset,
                 const blink::WebFloatSize& velocity) override;
 
   bool gesture_scroll_on_impl_thread_for_testing() const {
     return gesture_scroll_on_impl_thread_;
   }
 
+ protected:
+  void RecordMainThreadScrollingReasons(blink::WebInputEvent::Type type,
+                                        uint32_t reasons);
+
  private:
   friend class test::InputHandlerProxyTest;
 
   // Helper functions for handling more complicated input events.
   EventDisposition HandleMouseWheel(
       const blink::WebMouseWheelEvent& event);
   EventDisposition ScrollByMouseWheel(const blink::WebMouseWheelEvent& event);
   EventDisposition HandleGestureScrollBegin(
       const blink::WebGestureEvent& event);
   EventDisposition HandleGestureScrollUpdate(
@@ skipping 97 matching lines @@
   int32_t touch_start_result_;
 
   base::TimeTicks last_fling_animate_time_;
 
   DISALLOW_COPY_AND_ASSIGN(InputHandlerProxy);
 };
 
 }  // namespace ui
 
 #endif  // UI_EVENTS_BLINK_INPUT_HANDLER_PROXY_H_