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

skia/ext/platform_canvas.cc

 // 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.
 
 #include "skia/ext/platform_canvas.h"
 
 #include "skia/ext/bitmap_platform_device.h"
 #include "third_party/skia/include/core/SkTypes.h"
 
 namespace skia {
@@ skipping 36 matching lines @@
   if (width <= 0 || height <= 0)
     return;
 
   SkRect rect;
   rect.setXYWH(SkIntToScalar(x), SkIntToScalar(y),
                SkIntToScalar(width), SkIntToScalar(height));
   SkPaint paint;
   // so we don't draw anything on a device that ignores xfermodes
   paint.setColor(0);
   // install our custom mode
-  paint.setXfermode(new SkProcXfermode(MakeOpaqueXfermodeProc))->unref();
+  skia::RefPtr<SkProcXfermode> xfermode =
+      skia::AdoptRef(new SkProcXfermode(MakeOpaqueXfermodeProc));
+  paint.setXfermode(xfermode.get());
   canvas->drawRect(rect, paint);
 }
 
 size_t PlatformCanvasStrideForWidth(unsigned width) {
   return 4 * width;
 }
 
-SkCanvas* CreateCanvas(SkDevice* device, OnFailureType failureType) {
+SkCanvas* CreateCanvas(const skia::RefPtr<SkDevice>& device, OnFailureType failureType) {
   if (!device) {
     if (CRASH_ON_FAILURE == failureType)
       SK_CRASH();
     return NULL;
   }
-  SkAutoUnref aur(device);
-  return new SkCanvas(device);
+  return new SkCanvas(device.get());
 }
 
 PlatformBitmap::PlatformBitmap() : surface_(0), platform_extra_(0) {}
 
 }  // namespace skia