Move GetCursor() method from WindowDelegate to its own delegate interface CursorDelegate.

ui/aura/window.h

Index: ui/aura/window.h
diff --git a/ui/aura/window.h b/ui/aura/window.h
index f456687f15129c362a46b93818c016aa2ee5a042..a30df6b1f9f15e20859c2f6faf6a72d7dc2bde2a 100644
--- a/ui/aura/window.h
+++ b/ui/aura/window.h
@@ -217,9 +217,6 @@ class AURA_EXPORT Window : public ui::LayerDelegate,
   // Moves the cursor to the specified location relative to the window.
   virtual void MoveCursorTo(const gfx::Point& point_in_window);
 
-  // Returns the cursor for the specified point, in window coordinates.
-  gfx::NativeCursor GetCursor(const gfx::Point& point) const;
-
   // Sets an 'event filter' for the window. An 'event filter' for a Window is
   // a pre-target event handler, where the window owns the handler. A window
   // can have only one such event filter. Setting a new filter removes and