Coverity: Fix a pass-by-value.

ui/base/events.h

 // Copyright (c) 2012 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_BASE_EVENTS_H_
 #define UI_BASE_EVENTS_H_
 #pragma once
 
 #include "base/event_types.h"
 #include "ui/base/keycodes/keyboard_codes.h"
@@ skipping 153 matching lines @@
 // scrolled. |x_offset| and |y_offset| can be NULL.
 UI_EXPORT bool GetScrollOffsets(const base::NativeEvent& native_event,
                                 float* x_offset,
                                 float* y_offset);
 
 UI_EXPORT bool GetGestureTimes(const base::NativeEvent& native_event,
                                double* start_time,
                                double* end_time);
 
 // Returns true if event is noop.
-UI_EXPORT bool IsNoopEvent(base::NativeEvent event);
+UI_EXPORT bool IsNoopEvent(const base::NativeEvent& event);
 
 // Creates and returns no-op event.
 UI_EXPORT base::NativeEvent CreateNoopEvent();
 
 }  // namespace ui
 
 #endif  // UI_BASE_EVENTS_H_