aura-x11: Add support for xmodmap'ed pointer buttons.

ui/base/events.h

 // Copyright (c) 2011 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 62 matching lines @@
 // Get the EventType from a native event.
 UI_EXPORT EventType EventTypeFromNative(const base::NativeEvent& native_event);
 
 // Get the EventFlags from a native event.
 UI_EXPORT int EventFlagsFromNative(const base::NativeEvent& native_event);
 
 // Get the location from a native event.
 UI_EXPORT gfx::Point EventLocationFromNative(
     const base::NativeEvent& native_event);
 
+#if defined(USE_X11)
+// Returns the 'real' button for an event. The button reported in slave events
+// does not take into account any remapping (e.g. using xmodmap), while the
+// button reported in master events do. This is a utility function to always
+// return the mapped button.
+UI_EXPORT int EventButtonFromNative(const base::NativeEvent& native_event);
+#endif
+
 // Returns the KeyboardCode from a native event.
 UI_EXPORT KeyboardCode KeyboardCodeFromNative(
     const base::NativeEvent& native_event);
 
 // Returns true if the message is a mouse event.
 UI_EXPORT bool IsMouseEvent(const base::NativeEvent& native_event);
 
 // Gets the mouse wheel offset from a native event.
 UI_EXPORT int GetMouseWheelOffset(const base::NativeEvent& native_event);
 
 // Gets the touch id from a native event.
 UI_EXPORT int GetTouchId(const base::NativeEvent& native_event);
 
 // Gets the radius along the X/Y axis from a native event. Default is 1.0.
 UI_EXPORT float GetTouchRadiusX(const base::NativeEvent& native_event);
 UI_EXPORT float GetTouchRadiusY(const base::NativeEvent& native_event);
 
 // Gets the angle of the major axis away from the X axis. Default is 0.0.
 UI_EXPORT float GetTouchAngle(const base::NativeEvent& native_event);
 
 // Gets the force from a native_event. Normalized to be [0, 1]. Default is 0.0.
 UI_EXPORT float GetTouchForce(const base::NativeEvent& native_event);
 
 // Creates and returns no-op event.
 UI_EXPORT base::NativeEvent CreateNoopEvent();
 
 }  // namespace ui
 
 #endif  // UI_BASE_EVENTS_H_