Disable touch calibration on external touchscreen.

ash/host/root_window_host_factory_win.cc

Index: ash/host/root_window_host_factory_win.cc
diff --git a/ash/host/root_window_host_factory_win.cc b/ash/host/root_window_host_factory_win.cc
index 1703b727dbaf308d3339e4aabc90fc9e31906cc5..d2e2876e1ec02b330090985993b4e515919f0fa1 100644
--- a/ash/host/root_window_host_factory_win.cc
+++ b/ash/host/root_window_host_factory_win.cc
@@ -16,11 +16,13 @@ class RootWindowHostFactoryImpl : public ash::RootWindowHostFactory {
 
   // Overridden from RootWindowHostFactory:
   virtual aura::RootWindowHost* CreateRootWindowHost(
-      const gfx::Rect& initial_bounds) OVERRIDE {
+      const gfx::Rect& initial_bounds,
+      bool is_internal_display) OVERRIDE {
     if (base::win::GetVersion() >= base::win::VERSION_WIN8)
-      return aura::RemoteRootWindowHostWin::Create(initial_bounds);
+      return aura::RemoteRootWindowHostWin::Create(initial_bounds,
+                                                   is_internal_display);
 
-    return aura::RootWindowHost::Create(initial_bounds);
+    return aura::RootWindowHost::Create(initial_bounds, is_internal_display);
   }
 };