Disable touch calibration on external touchscreen.

ui/aura/root_window_host.h

Index: ui/aura/root_window_host.h
diff --git a/ui/aura/root_window_host.h b/ui/aura/root_window_host.h
index 2a07cea020f3c21064e9ef120c8807d3f3d7f495..d37dea3137361bf4a56e1141849829a17f5c83a9 100644
--- a/ui/aura/root_window_host.h
+++ b/ui/aura/root_window_host.h
@@ -33,7 +33,8 @@ class AURA_EXPORT RootWindowHost {
   virtual ~RootWindowHost() {}
 
   // Creates a new RootWindowHost. The caller owns the returned value.
-  static RootWindowHost* Create(const gfx::Rect& bounds);
+  static RootWindowHost* Create(const gfx::Rect& bounds,
+                                bool is_internal_display);
 
   // Returns the actual size of the screen.
   // (gfx::Screen only reports on the virtual desktop exposed by Aura.)