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

skia/ext/vector_canvas.h

Index: skia/ext/vector_canvas.h
diff --git a/skia/ext/vector_canvas.h b/skia/ext/vector_canvas.h
index e7a67fce9d2153f7ed9f0112a930cd1de1fb315f..34a218fadec1be9e18808daabbd03796f505fcbb 100644
--- a/skia/ext/vector_canvas.h
+++ b/skia/ext/vector_canvas.h
@@ -7,6 +7,7 @@
 
 #include "base/compiler_specific.h"
 #include "skia/ext/platform_canvas.h"
+#include "skia/ext/refptr.h"
 
 class SkDevice;
 
@@ -19,7 +20,7 @@ namespace skia {
 class SK_API VectorCanvas : public PlatformCanvas {
  public:
   // Ownership of |device| is transfered to VectorCanvas.
-  explicit VectorCanvas(SkDevice* device);
+  explicit VectorCanvas(const skia::RefPtr<SkDevice>& device);
   virtual ~VectorCanvas();
 
   virtual SkBounder* setBounder(SkBounder* bounder) OVERRIDE;