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

chrome/renderer/print_web_view_helper_mac.mm

 // 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 "chrome/renderer/print_web_view_helper.h"
 
 #import <AppKit/AppKit.h>
 
 #include "base/logging.h"
 #include "base/mac/scoped_nsautorelease_pool.h"
@@ skipping 104 matching lines @@
 
   gfx::Rect canvas_area =
       params.display_header_footer ? gfx::Rect(*page_size) : content_area;
 
   {
     SkDevice* device = metafile->StartPageForVectorCanvas(
         *page_size, canvas_area, scale_factor);
     if (!device)
       return;
 
-    SkRefPtr<skia::VectorCanvas> canvas = new skia::VectorCanvas(device);
-    canvas->unref();  // SkRefPtr and new both took a reference.
+    skia::RefPtr<skia::VectorCanvas> canvas =
+        skia::AdoptRef(new skia::VectorCanvas(device));
     WebKit::WebCanvas* canvas_ptr = canvas.get();
     printing::MetafileSkiaWrapper::SetMetafileOnCanvas(*canvas, metafile);
     skia::SetIsDraftMode(*canvas, is_print_ready_metafile_sent_);
     skia::SetIsPreviewMetafile(*canvas, is_preview);
 
     if (print_pages_params_->params.display_header_footer) {
       PrintHeaderAndFooter(canvas_ptr, page_number + 1,
                            print_preview_context_.total_page_count(),
                            scale_factor, page_layout_in_points,
                            *header_footer_info_, params);
     }
     RenderPageContent(frame, page_number, canvas_area, content_area,
                       scale_factor, canvas_ptr);
   }
 
   // Done printing. Close the device context to retrieve the compiled metafile.
   metafile->FinishPage();
 }