Allow the cursor to warp even when a window is dragged

ash/display/display_controller.h

Index: ash/display/display_controller.h
diff --git a/ash/display/display_controller.h b/ash/display/display_controller.h
index 7a151fbfe1a0c12f72c40805f5a06e2265ef1512..f625ee55890c28979a57f901a4bc346485688cd7 100644
--- a/ash/display/display_controller.h
+++ b/ash/display/display_controller.h
@@ -68,6 +68,10 @@ class ASH_EXPORT DisplayController : public aura::DisplayObserver {
   }
   void SetSecondaryDisplayLayout(SecondaryDisplayLayout layout);
 
+  void set_dont_warp_mouse(bool dont_warp_mouse) {
+    dont_warp_mouse_ = dont_warp_mouse;
+  }
+
   // Warps the mouse cursor to an alternate root window when the
   // |point_in_root|, which is the location of the mouse cursor,
   // hits or exceeds the edge of the |root_window| and the mouse cursor
@@ -96,6 +100,9 @@ class ASH_EXPORT DisplayController : public aura::DisplayObserver {
 
   SecondaryDisplayLayout secondary_display_layout_;
 
+  // If true, the mouse pointer can't move from one display to another.
+  bool dont_warp_mouse_;
+
   DISALLOW_COPY_AND_ASSIGN(DisplayController);
 };