Implement srcRect and dstRect functionality in SkBitmapSource. This is required for the "preserveAs…

gm/tileimagefilter.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 "gm.h"
 #include "SkTileImageFilter.h"
 #include "SkBitmapSource.h"
@@ skipping 52 matching lines @@
         }
     }
 
     virtual SkISize onISize() {
         return make_isize(WIDTH, HEIGHT);
     }
 
     void drawClippedBitmap(SkCanvas* canvas, const SkBitmap& bitmap, const SkPaint& paint,
                            SkScalar x, SkScalar y) {
         canvas->save();
-        canvas->clipRect(SkRect::MakeXYWH(x, y,
+        canvas->translate(x, y);
+        canvas->clipRect(SkRect::MakeXYWH(0, 0,
             SkIntToScalar(bitmap.width()), SkIntToScalar(bitmap.height())));
-        canvas->drawBitmap(bitmap, x, y, &paint);
+        canvas->drawBitmap(bitmap, 0, 0, &paint);
         canvas->restore();
     }
 
     virtual void onDraw(SkCanvas* canvas) {
         if (!fInitialized) {
             make_bitmap();
             make_checkerboard();
             fInitialized = true;
         }
         canvas->clear(0x00000000);
@@ skipping 27 matching lines @@
     SkBitmap fBitmap, fCheckerboard;
     bool fInitialized;
 };
 
 //////////////////////////////////////////////////////////////////////////////
 
 static GM* MyFactory(void*) { return new TileImageFilterGM; }
 static GMRegistry reg(MyFactory);
 
 }