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

printing/metafile_skia_wrapper.cc

 // 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.
 
 #include "printing/metafile_skia_wrapper.h"
 #include "skia/ext/platform_device.h"
+#include "skia/ext/refptr.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 #include "third_party/skia/include/core/SkDevice.h"
 #include "third_party/skia/include/core/SkMetaData.h"
 
 namespace printing {
 
 namespace {
 
 const char* kMetafileKey = "CrMetafile";
 const char* kCustomScaleKey = "CrCustomScale";
 
 }  // namespace
 
 // static
 void MetafileSkiaWrapper::SetMetafileOnCanvas(const SkCanvas& canvas,
                                               Metafile* metafile) {
-  MetafileSkiaWrapper* wrapper = NULL;
+  skia::RefPtr<MetafileSkiaWrapper> wrapper;
   if (metafile)
     wrapper = new MetafileSkiaWrapper(metafile);
 
   SkMetaData& meta = skia::getMetaData(canvas);
-  meta.setRefCnt(kMetafileKey, wrapper);
-  SkSafeUnref(wrapper);
+  meta.setRefCnt(kMetafileKey, wrapper.get());
 }
 
 // static
 Metafile* MetafileSkiaWrapper::GetMetafileFromCanvas(const SkCanvas& canvas) {
   SkMetaData& meta = skia::getMetaData(canvas);
   SkRefCnt* value;
   if (!meta.findRefCnt(kMetafileKey, &value) || !value)
     return NULL;
 
   return static_cast<MetafileSkiaWrapper*>(value)->metafile_;
@@ skipping 16 matching lines @@
 
   *scale = SkScalarToFloat(value);
   return true;
 }
 
 MetafileSkiaWrapper::MetafileSkiaWrapper(Metafile* metafile)
     : metafile_(metafile) {
 }
 
 }  // namespace printing