Change device IDs from unsigned to signed.

ash/display/display_info.h

 // Copyright (c) 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 ASH_DISPLAY_DISPLAY_INFO_H_
 #define ASH_DISPLAY_DISPLAY_INFO_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 93 matching lines @@
   bool has_overscan() const { return has_overscan_; }
 
   void set_rotation(gfx::Display::Rotation rotation) { rotation_ = rotation; }
   gfx::Display::Rotation rotation() const { return rotation_; }
 
   void set_touch_support(gfx::Display::TouchSupport support) {
     touch_support_ = support;
   }
   gfx::Display::TouchSupport touch_support() const { return touch_support_; }
 
-  void set_touch_device_id(unsigned int id) { touch_device_id_ = id; }
-  unsigned int touch_device_id() const { return touch_device_id_; }
+  void set_touch_device_id(int id) { touch_device_id_ = id; }
+  int touch_device_id() const { return touch_device_id_; }
 
   // Gets/Sets the device scale factor of the display.
   float device_scale_factor() const { return device_scale_factor_; }
   void set_device_scale_factor(float scale) { device_scale_factor_ = scale; }
 
   // The native bounds for the display. The size of this can be
   // different from the |size_in_pixel| when overscan insets are set
   // and/or |configured_ui_scale_| is set.
   const gfx::Rect& bounds_in_native() const {
     return bounds_in_native_;
@@ skipping 103 matching lines @@
   bool Use125DSFRorUIScaling() const;
 
   int64 id_;
   std::string name_;
   bool has_overscan_;
   gfx::Display::Rotation rotation_;
   gfx::Display::TouchSupport touch_support_;
 
   // If the display is also a touch device, it will have a positive
   // |touch_device_id_|. Otherwise |touch_device_id_| is 0.
-  unsigned int touch_device_id_;
+  int touch_device_id_;
 
   // This specifies the device's pixel density. (For example, a
   // display whose DPI is higher than the threshold is considered to have
   // device_scale_factor = 2.0 on Chrome OS).  This is used by the
   // grapics layer to choose and draw appropriate images and scale
   // layers properly.
   float device_scale_factor_;
   gfx::Rect bounds_in_native_;
 
   // The size of the display in use. The size can be different from the size
@@ skipping 29 matching lines @@
 
   // The list of available variations for the color calibration.
   std::vector<ui::ColorCalibrationProfile> available_color_profiles_;
 
   // If you add a new member, you need to update Copy().
 };
 
 }  // namespace ash
 
 #endif  //  ASH_DISPLAY_DISPLAY_INFO_H_