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

mojo/examples/aura_demo/aura_demo.cc

Index: mojo/examples/aura_demo/aura_demo.cc
diff --git a/mojo/examples/aura_demo/aura_demo.cc b/mojo/examples/aura_demo/aura_demo.cc
index 0b4b5e65b3d286504364858774db78901f367564..a65036a435b844368d7d1f966fc291124ab17758 100644
--- a/mojo/examples/aura_demo/aura_demo.cc
+++ b/mojo/examples/aura_demo/aura_demo.cc
@@ -54,6 +54,9 @@
 
   virtual void OnBoundsChanged(const gfx::Rect& old_bounds,
                                const gfx::Rect& new_bounds) OVERRIDE {}
+  virtual gfx::NativeCursor GetCursor(const gfx::Point& point) OVERRIDE {
+    return gfx::kNullCursor;
+  }
   virtual int GetNonClientComponent(const gfx::Point& point) const OVERRIDE {
     return HTCAPTION;
   }