touch: Change how touch-screen capability is processed.

ui/events/devices/touchscreen_device.h

 // Copyright 2014 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_DEVICES_TOUCHSCREEN_DEVICE_H_
 #define UI_EVENTS_DEVICES_TOUCHSCREEN_DEVICE_H_
 
 #include <string>
 
 #include "ui/events/devices/events_devices_export.h"
 #include "ui/events/devices/input_device.h"
 #include "ui/gfx/geometry/size.h"
 
 namespace ui {
 
 // Represents a Touchscreen device state.
 struct EVENTS_DEVICES_EXPORT TouchscreenDevice : public InputDevice {
   // Creates an invalid touchscreen device.
   TouchscreenDevice();
 
   TouchscreenDevice(unsigned int id,
                     InputDeviceType type,
                     const std::string& name,
-                    const gfx::Size& size);
+                    const gfx::Size& size,
+                    int touch_points);
 
-  // Size of the touch screen area.
-  gfx::Size size;
+  gfx::Size size;    // Size of the touch screen area.
+  int touch_points;  // The number of touch points this device supports (0 if
+                     // unknown).
 };
 
 }  // namespace ui
 
 #endif  // UI_EVENTS_DEVICES_TOUCHSCREEN_DEVICE_H_