Add SkImage->draw() call with src and dst rects.

src/image/SkImage_Base.h

Index: src/image/SkImage_Base.h
diff --git a/src/image/SkImage_Base.h b/src/image/SkImage_Base.h
index 9ae13de4aed7c0a3ef20fb9c6f648ec2fd04ceb2..431444dadb973a7be0bbaf36da1771114344adc1 100644
--- a/src/image/SkImage_Base.h
+++ b/src/image/SkImage_Base.h
@@ -15,6 +15,8 @@ public:
     SkImage_Base(int width, int height) : INHERITED(width, height) {}
 
     virtual void onDraw(SkCanvas*, SkScalar x, SkScalar y, const SkPaint*) = 0;
+    virtual void onDrawRectToRect(SkCanvas*, const SkRect* src, 
+                                  const SkRect& dst, const SkPaint*) = 0;
     virtual GrTexture* onGetTexture() { return NULL; }
 
     // return a read-only copy of the pixels. We promise to not modify them,