Add skia::RefPtr class to wrap ref counted classes from Skia.

skia/ext/bitmap_platform_device_mac.h

 // 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.
 
 #ifndef SKIA_EXT_BITMAP_PLATFORM_DEVICE_MAC_H_
 #define SKIA_EXT_BITMAP_PLATFORM_DEVICE_MAC_H_
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "skia/ext/platform_device.h"
+#include "skia/ext/refptr.h"
 
 namespace skia {
 
 // A device is basically a wrapper around SkBitmap that provides a surface for
 // SkCanvas to draw into. Our device provides a surface CoreGraphics can also
 // write to. BitmapPlatformDevice creates a bitmap using
 // CGCreateBitmapContext() in a format that Skia supports and can then use this
 // to draw text into, etc. This pixel data is provided to the bitmap that the
 // device contains so that it can be shared.
 //
@@ skipping 36 matching lines @@
   // SkDevice overrides
   virtual void setMatrixClip(const SkMatrix& transform, const SkRegion& region,
                              const SkClipStack&) OVERRIDE;
 
  protected:
   // Reference counted data that can be shared between multiple devices. This
   // allows copy constructors and operator= for devices to work properly. The
   // bitmaps used by the base device class are already refcounted and copyable.
   class BitmapPlatformDeviceData;
 
-  BitmapPlatformDevice(BitmapPlatformDeviceData* data,
+  BitmapPlatformDevice(const skia::RefPtr<BitmapPlatformDeviceData>& data,
                        const SkBitmap& bitmap);
 
   // Flushes the CoreGraphics context so that the pixel data can be accessed
   // directly by Skia. Overridden from SkDevice, this is called when Skia
   // starts accessing pixel data.
   virtual const SkBitmap& onAccessBitmap(SkBitmap*) OVERRIDE;
 
   virtual SkDevice* onCreateCompatibleDevice(SkBitmap::Config, int width,
                                              int height, bool isOpaque,
                                              Usage usage) OVERRIDE;
 
-  // Data associated with this device, guaranteed non-null. We hold a reference
-  // to this object.
-  BitmapPlatformDeviceData* data_;
+  // Data associated with this device, guaranteed non-null.
+  skia::RefPtr<BitmapPlatformDeviceData> data_;
 
   DISALLOW_COPY_AND_ASSIGN(BitmapPlatformDevice);
 };
 
 }  // namespace skia
 
 #endif  // SKIA_EXT_BITMAP_PLATFORM_DEVICE_MAC_H_