Adds switch to disable generating mouse events from touch events and

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 34 matching lines @@
   ET_DROP_TARGET_EVENT,
   ET_FOCUS_CHANGE,
   ET_TRANSLATED_KEY_PRESS,
   ET_TRANSLATED_KEY_RELEASE,
 
   // GestureEvent types
   ET_GESTURE_SCROLL_BEGIN,
   ET_GESTURE_SCROLL_END,
   ET_GESTURE_SCROLL_UPDATE,
   ET_GESTURE_TAP,
-  ET_GESTURE_TAP_DOWN,
-  ET_GESTURE_TAP_UP,
+  ET_GESTURE_TAP_DOWN,  // Sent before any other gesture types.
+  ET_GESTURE_TAP_UP,    // Sent after any other gestures.
   ET_GESTURE_DOUBLE_TAP,
   ET_GESTURE_PINCH_BEGIN,
   ET_GESTURE_PINCH_END,
   ET_GESTURE_PINCH_UPDATE,
   ET_GESTURE_LONG_PRESS,
   // A SWIPE gesture can happen at the end of a TAP_UP gesture if the
   // finger(s) were moving quickly before they are released.
   ET_GESTURE_MULTIFINGER_SWIPE,
 
   // Scroll support.
@@ skipping 141 matching lines @@
 // Creates and returns no-op event.
 UI_EXPORT base::NativeEvent CreateNoopEvent();
 
 #if defined(OS_WIN)
 UI_EXPORT int GetModifiersFromACCEL(const ACCEL& accel);
 #endif
 
 }  // namespace ui
 
 #endif  // UI_BASE_EVENTS_H_