Cancel drag if display configuration changes.

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 74502bfa128d00f5968a3198b9940180d44f4a46..57e3a4f38a3f55b295cd68b777bd3d47882c3c1f 100644
--- a/ui/aura/root_window_host.h
+++ b/ui/aura/root_window_host.h
@@ -105,6 +105,9 @@ class RootWindowHost {
 
   // Called when the device scale factor of the root window has chagned.
   virtual void OnDeviceScaleFactorChanged(float device_scale_factor) = 0;
+
+  // Stop listening events in preparation for shutdown.
+  virtual void StopListeningEvents() = 0;
 };
 
 }  // namespace aura