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

ui/aura/window_delegate.h

Index: ui/aura/window_delegate.h
diff --git a/ui/aura/window_delegate.h b/ui/aura/window_delegate.h
index 516d4447248878ea15865aa4181e5661632f8902..7a4f5500097327e7ca1e9b2a1d4a1ae1b97bcdff 100644
--- a/ui/aura/window_delegate.h
+++ b/ui/aura/window_delegate.h
@@ -43,6 +43,10 @@
   // Called when the Window's position and/or size changes.
   virtual void OnBoundsChanged(const gfx::Rect& old_bounds,
                                const gfx::Rect& new_bounds) = 0;
+
+  // Returns the native cursor for the specified point, in window coordinates,
+  // or NULL for the default cursor.
+  virtual gfx::NativeCursor GetCursor(const gfx::Point& point) = 0;
 
   // Returns the non-client component (see hit_test.h) containing |point|, in
   // window coordinates.