Change device IDs from unsigned to signed.

ash/touch/touch_transformer_controller.cc

 // 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.
 
 #include "ash/touch/touch_transformer_controller.h"
 
 #include "ash/display/display_controller.h"
 #include "ash/display/display_manager.h"
 #include "ash/host/ash_window_tree_host.h"
 #include "ash/root_window_controller.h"
 #include "ash/shell.h"
 #include "ui/aura/window_tree_host.h"
 #include "ui/display/chromeos/display_configurator.h"
 #include "ui/display/types/display_snapshot.h"
 #include "ui/events/devices/device_data_manager.h"
 
 namespace ash {
 
 namespace {
 
 DisplayManager* GetDisplayManager() {
   return Shell::GetInstance()->display_manager();
 }
 
-ui::TouchscreenDevice FindTouchscreenById(unsigned int id) {
+ui::TouchscreenDevice FindTouchscreenById(int id) {
   const std::vector<ui::TouchscreenDevice>& touchscreens =
       ui::DeviceDataManager::GetInstance()->touchscreen_devices();
   for (const auto& touchscreen : touchscreens) {
     if (touchscreen.id == id)
       return touchscreen;
   }
 
   return ui::TouchscreenDevice();
 }
 
@@ skipping 200 matching lines @@
 
 void TouchTransformerController::OnDisplaysInitialized() {
   UpdateTouchTransformer();
 }
 
 void TouchTransformerController::OnDisplayConfigurationChanged() {
   UpdateTouchTransformer();
 }
 
 }  // namespace ash