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

ui/gfx/display.h

Index: ui/gfx/display.h
diff --git a/ui/gfx/display.h b/ui/gfx/display.h
index 324b96134e933e6be7a7648baaa8fdf2b66c4979..eb35a5f5c6f76cd60c7e928e649630636df8e3b0 100644
--- a/ui/gfx/display.h
+++ b/ui/gfx/display.h
@@ -30,6 +30,13 @@ class GFX_EXPORT Display {
     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);
@@ -67,6 +74,9 @@ class GFX_EXPORT Display {
   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(); }
@@ -113,6 +123,7 @@ class GFX_EXPORT Display {
   Rect work_area_;
   float device_scale_factor_;
   Rotation rotation_;
+  TouchSupport touch_support_;
 };
 
 }  // namespace gfx