Disable touch calibration on external touchscreen.

ui/aura/root_window_host_linux.h

Index: ui/aura/root_window_host_linux.h
diff --git a/ui/aura/root_window_host_linux.h b/ui/aura/root_window_host_linux.h
index 85fcd3b30d7392158b214e04df5a35b048e7b2fb..031c4be00e42e2f66673142f1b6d81a1d55ce99b 100644
--- a/ui/aura/root_window_host_linux.h
+++ b/ui/aura/root_window_host_linux.h
@@ -32,7 +32,8 @@ class TouchEventCalibrate;
 class RootWindowHostLinux : public RootWindowHost,
                             public MessageLoop::Dispatcher {
  public:
-  explicit RootWindowHostLinux(const gfx::Rect& bounds);
+  explicit RootWindowHostLinux(const gfx::Rect& bounds,
+                               bool is_internal_display);
   virtual ~RootWindowHostLinux();
 
   // Overridden from Dispatcher overrides:
@@ -126,6 +127,9 @@ class RootWindowHostLinux : public RootWindowHost,
 
   ui::X11AtomCache atom_cache_;
 
+  // True if RootWindow corresponds to an internal display (on ChromeOS).
+  bool is_internal_display_;
+
   DISALLOW_COPY_AND_ASSIGN(RootWindowHostLinux);
 };