Make drawImage a virtual on SkDevice

src/core/SkPaintPriv.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkPaintPriv.h"
 
 #include "SkBitmap.h"
 #include "SkColorFilter.h"
+#include "SkImage.h"
 #include "SkPaint.h"
 #include "SkShader.h"
 
 bool isPaintOpaque(const SkPaint* paint, SkPaintBitmapOpacity contentType) {
     if (!paint) {
         return contentType != kUnknown_SkPaintBitmapOpacity;
     }
     SkXfermode::SrcColorOpacity opacityType = SkXfermode::kUnknown_SrcColorOpacity;
 
     if (!paint->getColorFilter() ||
@@ skipping 20 matching lines @@
 
     if(!bmpReplacesShader)
         contentType = kNoBitmap_SkPaintBitmapOpacity;
     else if(bmpReplacesShader->isOpaque())
         contentType = kOpaque_SkPaintBitmapOpacity;
     else
         contentType = kUnknown_SkPaintBitmapOpacity;
 
     return isPaintOpaque(paint, contentType);
 }
+
+bool isPaintOpaque(const SkPaint* paint, const SkImage* image) {
+    return isPaintOpaque(paint, image->isOpaque() ?
+                         kOpaque_SkPaintBitmapOpacity : kUnknown_SkPaintBitmapOpacity);
+}