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

mojo/examples/aura_demo/aura_demo.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <stdio.h>
 #include <string>
 
 #include "base/at_exit.h"
 #include "base/command_line.h"
 #include "base/message_loop/message_loop.h"
@@ skipping 36 matching lines @@
   virtual gfx::Size GetMinimumSize() const OVERRIDE {
     return gfx::Size();
   }
 
   virtual gfx::Size GetMaximumSize() const OVERRIDE {
     return gfx::Size();
   }
 
   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;
   }
   virtual bool ShouldDescendIntoChildForEventHandling(
       aura::Window* child,
       const gfx::Point& location) OVERRIDE {
     return true;
   }
   virtual bool CanFocus() OVERRIDE { return true; }
   virtual void OnCaptureLost() OVERRIDE {}
@@ skipping 119 matching lines @@
 
   // TODO(beng): This crashes in a DCHECK on X11 because this thread's
   //             MessageLoop is not of TYPE_UI. I think we need a way to build
   //             Aura that doesn't define platform-specific stuff.
   aura::Env::CreateInstance();
   mojo::examples::AuraDemo app(shell_handle);
   loop.Run();
 
   return MOJO_RESULT_OK;
 }