add legacy/helper allocN32Pixels, and convert gm to use it

gm/bitmapmatrix.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 "gm.h"
 #include "SkBitmap.h"
 #include "SkBlurMask.h"
@@ skipping 89 matching lines @@
             canvas->translate(0, SkIntToScalar(20));
             canvas->drawBitmapMatrix(bm, matrix, &paint);
             canvas->restore();
         }
 
     }
 private:
     void setupBitmap(SkBitmap* bm) {
         SkASSERT(bm);
         static const int SIZE = 64;
-        bm->setConfig(SkBitmap::kARGB_8888_Config, SIZE, SIZE);
-        bm->allocPixels();
+        bm->allocN32Pixels(SIZE, SIZE);
         SkCanvas canvas(*bm);
 
         SkPaint paint;
         paint.setColor(SK_ColorGREEN);
         canvas.drawPaint(paint);
 
         paint.setColor(SK_ColorBLUE);
         paint.setAntiAlias(true);
         SkRect rect = SkRect::MakeWH(SkIntToScalar(SIZE), SkIntToScalar(SIZE));
         SkPath path;
         path.addOval(rect);
         canvas.drawPath(path, paint);
     }
 };
 
 ////////////////////////////////////////////////////////////////////////////////
 
 static GM* MyFactory(void*) { return new DrawBitmapMatrixGM; }
 static GMRegistry reg(MyFactory);
 
 }