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

ui/wm/public/cursor_delegate.h

+// Copyright 2014 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.
+
+#ifndef UI_WM_PUBLIC_CURSOR_DELEGATE_H_
+#define UI_WM_PUBLIC_CURSOR_DELEGATE_H_
+
+#include "ui/gfx/native_widget_types.h"
+#include "ui/wm/core/wm_core_export.h"
+
+namespace aura {
+class Window;
+}
+
+namespace gfx {
+class Point;
+}
+
+namespace wm {
+
+class WM_CORE_EXPORT CursorDelegate {
+ public:
+  virtual gfx::NativeCursor GetCursorForPoint(const gfx::Point& point) = 0;
+
+ protected:
+  virtual ~CursorDelegate() {}
+};
+
+WM_CORE_EXPORT void SetCursorDelegate(aura::Window* window,
+                                      CursorDelegate* delegate);
+WM_CORE_EXPORT CursorDelegate* GetCursorDelegate(aura::Window* window);
+
+}  // namespace wm
+
+#endif  // UI_WM_PUBLIC_CURSOR_DELEGATE_H_