Eliminates all ash dependencies from WindowModalityController.

ui/views/corewm/window_util.h

Index: ui/views/corewm/window_util.h
===================================================================
--- ui/views/corewm/window_util.h	(revision 170295)
+++ ui/views/corewm/window_util.h	(working copy)
@@ -19,6 +19,15 @@
 namespace views {
 namespace corewm {
 
+VIEWS_EXPORT void ActivateWindow(aura::Window* window);
+VIEWS_EXPORT void DeactivateWindow(aura::Window* window);
+VIEWS_EXPORT bool IsActiveWindow(aura::Window* window);
+VIEWS_EXPORT bool CanActivateWindow(aura::Window* window);
+
+// Retrieves the activatable window for |window|. The ActivationClient makes
+// this determination.
+VIEWS_EXPORT aura::Window* GetActivatableWindow(aura::Window* window);
+
 // Deletes |layer| and all its child layers.
 VIEWS_EXPORT void DeepDeleteLayers(ui::Layer* layer);