cros: Default to natural scrolling if the internal diplay is a touchscreen.

ash/display/display_change_observer_chromeos.cc

 // Copyright 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.
 
 #include "ash/display/display_change_observer_chromeos.h"
 
 #include <algorithm>
 #include <map>
 #include <set>
 #include <vector>
@@ skipping 179 matching lines @@
     int64 id = output.display_id;
     if (id == gfx::Display::kInvalidDisplayID || ids.find(id) != ids.end())
       id = output.index;
     ids.insert(id);
 
     displays.push_back(DisplayInfo(id, name, has_overscan));
     displays.back().set_device_scale_factor(device_scale_factor);
     displays.back().SetBounds(display_bounds);
     displays.back().set_native(true);
     displays.back().set_resolutions(resolutions);
+    displays.back().set_touch_support(
+        output.touch_device_id == 0 ? gfx::Display::TOUCH_SUPPORT_UNAVAILABLE :
+                                      gfx::Display::TOUCH_SUPPORT_AVAILABLE);
   }
 
   // DisplayManager can be null during the boot.
   Shell::GetInstance()->display_manager()->OnNativeDisplaysChanged(displays);
 }
 
 void DisplayChangeObserver::OnAppTerminating() {
 #if defined(USE_ASH)
   // Stop handling display configuration events once the shutdown
   // process starts. crbug.com/177014.
   Shell::GetInstance()->output_configurator()->Stop();
 #endif
 }
 
 }  // namespace internal
 }  // namespace ash