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

src/image/SkImagePriv.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkImagePriv.h"
 #include "SkCanvas.h"
 #include "SkPicture.h"
@@ skipping 123 matching lines @@
         canvas->saveLayer(&bounds, paint);
         canvas->translate(x, y);
     } else if (x || y) {
         canvas->save();
         canvas->translate(x, y);
     }
 
     canvas->drawPicture(*picture);
     canvas->restoreToCount(saveCount);
 }
+
+void SkImagePrivDrawPicture(SkCanvas* canvas, SkPicture* picture,

[Justin Novosad, 2013/07/18 21:54:37]

You need to write a good test for this function.  I<m not sure we need this
override to be implemented. You could leave it empty with something like: 
SkASSERT(0); // Not implemented

+                            SkRect src, SkRect dst, const SkPaint* paint) {
+    int saveCount = canvas->getSaveCount();

[Justin Novosad, 2013/07/18 21:54:37]

No need for this call. This value is returned by saveLayer

+
+    canvas->clipRect(src);

[Justin Novosad, 2013/07/18 21:54:37]

Bug: This clip does not get undone.  Also I think it needs to be applied just
before the call to drawPictures.

+    canvas->saveLayer(&dst, paint);

[reed1, 2013/07/19 14:03:45]

Why saveLayer instead of just save?

+    canvas->translate(dst.x(), dst.y());

[Justin Novosad, 2013/07/18 21:54:37]

This is not the right transform to map src to dst. 

[reed1, 2013/07/19 14:03:45]

SkMatrix has a mapRectToRect helper function you can use, which you could then
concat() onto the canvas.

+
+    canvas->drawPicture(*picture);
+    canvas->restoreToCount(saveCount);
+}