Making CursorFactoryOzone thread-local

ui/ozone/public/cursor_factory_ozone.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_OZONE_PUBLIC_CURSOR_FACTORY_OZONE_H_
 #define UI_OZONE_PUBLIC_CURSOR_FACTORY_OZONE_H_
 
 #include <vector>
 
 #include "ui/gfx/native_widget_types.h"
 #include "ui/ozone/ozone_base_export.h"
 
 namespace gfx {
 class Point;
 }
 
 namespace ui {
 
 typedef void* PlatformCursor;
 
 class OZONE_BASE_EXPORT CursorFactoryOzone {
  public:
   CursorFactoryOzone();
   virtual ~CursorFactoryOzone();
 
-  // Returns the singleton instance.
+  // Returns the thread-local instance.
   static CursorFactoryOzone* GetInstance();
 
   // Return the default cursor of the specified type. The types are listed in
   // ui/base/cursor/cursor.h. Default cursors are managed by the implementation
   // and must live indefinitely; there's no way to know when to free them.
   virtual PlatformCursor GetDefaultCursor(CursorType type);
 
   // Return a image cursor from the specified image & hotspot. Image cursors
   // are referenced counted and have an initial refcount of 1. Therefore, each
   // CreateImageCursor call must be matched with a call to UnrefImageCursor.
   virtual PlatformCursor CreateImageCursor(const SkBitmap& bitmap,
                                            const gfx::Point& hotspot,
                                            float bitmap_dpi);
 
   // Return a animated cursor from the specified image & hotspot. Animated
   // cursors are referenced counted and have an initial refcount of 1.
   // Therefore, each CreateAnimatedCursor call must be matched with a call to
   // UnrefImageCursor.
   virtual PlatformCursor CreateAnimatedCursor(
       const std::vector<SkBitmap>& bitmaps,
       const gfx::Point& hotspot,
       int frame_delay_ms,
       float bitmap_dpi);
 
   // Increment platform image cursor refcount.
   virtual void RefImageCursor(PlatformCursor cursor);
 
   // Decrement platform image cursor refcount.
   virtual void UnrefImageCursor(PlatformCursor cursor);
-
- private:
-  static CursorFactoryOzone* impl_;  // not owned
 };
 
 }  // namespace ui
 
 #endif  // UI_OZONE_PUBLIC_CURSOR_FACTORY_OZONE_H_