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

ui/gfx/display.h

 // Copyright (c) 2012 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_GFX_DISPLAY_H_
 #define UI_GFX_DISPLAY_H_
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "ui/gfx/gfx_export.h"
@@ skipping 12 matching lines @@
 class GFX_EXPORT Display {
  public:
   // Screen Rotation in clock-wise degrees.
   enum Rotation {
     ROTATE_0 = 0,
     ROTATE_90,
     ROTATE_180,
     ROTATE_270,
   };
 
+  // Touch support for the display.
+  enum TouchSupport {
+    TOUCH_SUPPORT_UNKNOWN,
+    TOUCH_SUPPORT_AVAILABLE,
+    TOUCH_SUPPORT_UNAVAILABLE,
+  };
+
   // Creates a display with kInvalidDisplayID as default.
   Display();
   explicit Display(int64 id);
   Display(int64 id, const Rect& bounds);
   ~Display();
 
   // Returns the forced device scale factor, which is given by
   // "--force-device-scale-factor".
   static float GetForcedDeviceScaleFactor();
 
@@ skipping 17 matching lines @@
   // Output device's pixel scale factor. This specifies how much the
   // UI should be scaled when the actual output has more pixels than
   // standard displays (which is around 100~120dpi.) The potential return
   // values depend on each platforms.
   float device_scale_factor() const { return device_scale_factor_; }
   void set_device_scale_factor(float scale) { device_scale_factor_ = scale; }
 
   Rotation rotation() const { return rotation_; }
   void set_rotation(Rotation rotation) { rotation_ = rotation; }
 
+  TouchSupport touch_support() const { return touch_support_; }
+  void set_touch_support(TouchSupport support) { touch_support_ = support; }
+
   // Utility functions that just return the size of display and
   // work area.
   const Size& size() const { return bounds_.size(); }
   const Size& work_area_size() const { return work_area_.size(); }
 
   // Returns the work area insets.
   Insets GetWorkAreaInsets() const;
 
   // Sets the device scale factor and display bounds in pixel. This
   // updates the work are using the same insets between old bounds and
@@ skipping 26 matching lines @@
   static void SetInternalDisplayId(int64 internal_display_id);
 
   static const int64 kInvalidDisplayID;
 
  private:
   int64 id_;
   Rect bounds_;
   Rect work_area_;
   float device_scale_factor_;
   Rotation rotation_;
+  TouchSupport touch_support_;
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_DISPLAY_H_