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

skia/ext/platform_canvas.h

 // Copyright (c) 2011 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_PLATFORM_CANVAS_H_
 #define SKIA_EXT_PLATFORM_CANVAS_H_
 
 // The platform-specific device will include the necessary platform headers
 // to get the surface type.
 #include "base/basictypes.h"
 #include "skia/ext/platform_device.h"
+#include "skia/ext/refptr.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 
 namespace skia {
 
 typedef SkCanvas PlatformCanvas;
 
 //
 //  Note about error handling.
 //
 //  Creating a canvas can fail at times, most often because we fail to allocate
@@ skipping 42 matching lines @@
                                         uint8_t* data,
                                         OnFailureType failure_type);
 #endif
 
 static inline SkCanvas* CreatePlatformCanvas(int width,
                                              int height,
                                              bool is_opaque) {
   return CreatePlatformCanvas(width, height, is_opaque, 0, CRASH_ON_FAILURE);
 }
 
-// Takes ownership of the device, so the caller need not call unref().
-SK_API SkCanvas* CreateCanvas(SkDevice* device, OnFailureType failure_type);
+SK_API SkCanvas* CreateCanvas(const skia::RefPtr<SkDevice>& device,
+                              OnFailureType failure_type);
 
 static inline SkCanvas* CreateBitmapCanvas(int width,
                                            int height,
                                            bool is_opaque) {
   return CreatePlatformCanvas(width, height, is_opaque, 0, CRASH_ON_FAILURE);
 }
 
 static inline SkCanvas* TryCreateBitmapCanvas(int width,
                                               int height,
                                               bool is_opaque) {
@@ skipping 93 matching lines @@
   SkBitmap bitmap_;
   PlatformSurface surface_; // initialized to 0
   intptr_t platform_extra_; // initialized to 0, specific to each platform
 
   DISALLOW_COPY_AND_ASSIGN(PlatformBitmap);
 };
 
 }  // namespace skia
 
 #endif  // SKIA_EXT_PLATFORM_CANVAS_H_