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

ui/aura/test/test_window_delegate.cc

 // Copyright (c) 2012 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 "ui/aura/test/test_window_delegate.h"
 
 #include "base/strings/stringprintf.h"
 #include "ui/aura/window.h"
 #include "ui/base/hit_test.h"
 #include "ui/events/event.h"
@@ skipping 32 matching lines @@
 }
 
 gfx::Size TestWindowDelegate::GetMaximumSize() const {
   return maximum_size_;
 }
 
 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 {
   return window_component_;
 }
 
 bool TestWindowDelegate::ShouldDescendIntoChildForEventHandling(
       Window* child,
       const gfx::Point& location) {
   return true;
 }
 
@@ skipping 155 matching lines @@
 }
 
 int EventCountDelegate::GetGestureCountAndReset() {
   int gesture_count = gesture_count_;
   gesture_count_ = 0;
   return gesture_count;
 }
 
 }  // namespace test
 }  // namespace aura