Cancel drag if display configuration changes.

ash/wm/toplevel_window_event_filter.h

Index: ash/wm/toplevel_window_event_filter.h
diff --git a/ash/wm/toplevel_window_event_filter.h b/ash/wm/toplevel_window_event_filter.h
index de778def69512e2116466c3c4e6414f5ae4b7f87..310caea24008afead7b8153a34686dfba6c142b9 100644
--- a/ash/wm/toplevel_window_event_filter.h
+++ b/ash/wm/toplevel_window_event_filter.h
@@ -13,6 +13,7 @@
 #include "ui/aura/client/window_move_client.h"
 #include "ui/aura/event_filter.h"
 #include "ash/ash_export.h"
+#include "ash/display/display_controller.h"
 #include "ui/gfx/point.h"
 #include "ui/gfx/rect.h"
 
@@ -30,7 +31,8 @@ class WindowResizer;
 
 class ASH_EXPORT ToplevelWindowEventFilter :
       public aura::EventFilter,
-      public aura::client::WindowMoveClient {
+      public aura::client::WindowMoveClient,
+      public DisplayController::Observer {
  public:
   explicit ToplevelWindowEventFilter(aura::Window* owner);
   virtual ~ToplevelWindowEventFilter();
@@ -54,10 +56,14 @@ class ASH_EXPORT ToplevelWindowEventFilter :
       ui::GestureEvent* event) OVERRIDE;
 
   // Overridden form aura::client::WindowMoveClient:
-  virtual void RunMoveLoop(aura::Window* source,
-                           const gfx::Point& drag_offset) OVERRIDE;
+  virtual aura::client::WindowMoveResult RunMoveLoop(
+      aura::Window* source,
+      const gfx::Point& drag_offset) OVERRIDE;
   virtual void EndMoveLoop() OVERRIDE;
 
+  // Overridden form ash::DisplayController::Observer:
+  virtual void OnDisplayConfigurationChanging() OVERRIDE;
+
  protected:
   // Creates a new WindowResizer.
   virtual WindowResizer* CreateWindowResizer(aura::Window* window,
@@ -88,6 +94,10 @@ class ASH_EXPORT ToplevelWindowEventFilter :
   // Are we running a nested message loop from RunMoveLoop().
   bool in_move_loop_;
 
+  // Was the move operation cancelled? Used only when the nested loop
+  // is used to move a window.
+  bool move_cancelled_;
+
   // Is a gesture-resize in progress?
   bool in_gesture_resize_;