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

chrome/renderer/chrome_render_view_observer.cc

Index: chrome/renderer/chrome_render_view_observer.cc
diff --git a/chrome/renderer/chrome_render_view_observer.cc b/chrome/renderer/chrome_render_view_observer.cc
index f2b8e0956061470123fb5d624db5828ab8127daa..b1c510265d0b29bb5a76975666565fd38f57507f 100644
--- a/chrome/renderer/chrome_render_view_observer.cc
+++ b/chrome/renderer/chrome_render_view_observer.cc
@@ -818,13 +818,12 @@ bool ChromeRenderViewObserver::CaptureSnapshot(WebView* view,
   view->layout();
   const WebSize& size = view->size();
 
-  SkCanvas* canvas = skia::CreatePlatformCanvas(size.width, size.height, true,
-                                            NULL, skia::RETURN_NULL_ON_FAILURE);
+  skia::RefPtr<SkCanvas> canvas = skia::CreatePlatformCanvas(
+      size.width, size.height, true, NULL, skia::RETURN_NULL_ON_FAILURE);
   if (!canvas)
     return false;
 
-  SkAutoUnref au(canvas);
-  view->paint(webkit_glue::ToWebCanvas(canvas),
+  view->paint(webkit_glue::ToWebCanvas(canvas.get()),
               WebRect(0, 0, size.width, size.height));
   // TODO: Add a way to snapshot the whole page, not just the currently
   // visible part.