Make drawImage a virtual on SkDevice

include/core/SkDevice.h

Index: include/core/SkDevice.h
diff --git a/include/core/SkDevice.h b/include/core/SkDevice.h
index 8a219d7053b0cd662fcb6fa03ba64b908be199f1..b474687cfbf0ce4c8fda8ca4a958e59585cc3415 100644
--- a/include/core/SkDevice.h
+++ b/include/core/SkDevice.h
@@ -209,6 +209,10 @@ protected:
                                 const SkPaint& paint,
                                 SkCanvas::DrawBitmapRectFlags flags) = 0;
 
+    virtual void drawImage(const SkDraw&, const SkImage*, SkScalar x, SkScalar y, const SkPaint&);
+    virtual void drawImageRect(const SkDraw&, const SkImage*, const SkRect* src, const SkRect& dst,
+                               const SkPaint&);
+
     /**
      *  Does not handle text decoration.
      *  Decorations (underline and stike-thru) will be handled by SkCanvas.