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

ui/aura/test/test_window_delegate.cc

Index: ui/aura/test/test_window_delegate.cc
diff --git a/ui/aura/test/test_window_delegate.cc b/ui/aura/test/test_window_delegate.cc
index 96aa57fd32140afb8cb9888f592ac4c3c1819087..e5ae364b5fd28e7c8aeb460c6fa8ca9e5cec3093 100644
--- a/ui/aura/test/test_window_delegate.cc
+++ b/ui/aura/test/test_window_delegate.cc
@@ -48,6 +48,10 @@
 
 void TestWindowDelegate::OnBoundsChanged(const gfx::Rect& old_bounds,
                                          const gfx::Rect& new_bounds) {
+}
+
+gfx::NativeCursor TestWindowDelegate::GetCursor(const gfx::Point& point) {
+  return gfx::kNullCursor;
 }
 
 int TestWindowDelegate::GetNonClientComponent(const gfx::Point& point) const {