replace setConfig+allocPixels with single call

tests/PremulAlphaRoundTripTest.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBitmapDevice.h"
 #include "SkCanvas.h"
 #include "SkConfig8888.h"
 #include "Test.h"
 
 #if SK_SUPPORT_GPU
 #include "GrContextFactory.h"
 #include "SkGpuDevice.h"
 #endif
 
 static void fillCanvas(SkCanvas* canvas, SkCanvas::Config8888 unpremulConfig) {
     SkBitmap bmp;
-    bmp.setConfig(SkBitmap::kARGB_8888_Config, 256, 256);
-    bmp.allocPixels();
+    bmp.allocN32Pixels(256, 256);
     SkAutoLockPixels alp(bmp);
     uint32_t* pixels = reinterpret_cast<uint32_t*>(bmp.getPixels());
 
     for (int a = 0; a < 256; ++a) {
         for (int r = 0; r < 256; ++r) {
             pixels[a * 256 + r] = SkPackConfig8888(unpremulConfig, a, r, 0, 0);
         }
     }
     canvas->writePixels(bmp, 0, 0, unpremulConfig);
 }
@@ skipping 33 matching lines @@
                 }
 
                 device.reset(new SkGpuDevice(context, SkBitmap::kARGB_8888_Config, 256, 256));
 #else
                 continue;
 #endif
             }
             SkCanvas canvas(device);
 
             SkBitmap readBmp1;
-            readBmp1.setConfig(SkBitmap::kARGB_8888_Config, 256, 256);
-            readBmp1.allocPixels();
+            readBmp1.allocN32Pixels(256, 256);
             SkBitmap readBmp2;
-            readBmp2.setConfig(SkBitmap::kARGB_8888_Config, 256, 256);
-            readBmp2.allocPixels();
+            readBmp2.allocN32Pixels(256, 256);
 
             for (size_t upmaIdx = 0;
                  upmaIdx < SK_ARRAY_COUNT(gUnpremulConfigs);
                  ++upmaIdx) {
                 fillCanvas(&canvas, gUnpremulConfigs[upmaIdx]);
                 {
                     SkAutoLockPixels alp1(readBmp1);
                     SkAutoLockPixels alp2(readBmp2);
                     sk_bzero(readBmp1.getPixels(), readBmp1.getSafeSize());
                     sk_bzero(readBmp2.getPixels(), readBmp2.getSafeSize());
@@ skipping 13 matching lines @@
                 for (int y = 0; y < 256 && success; ++y) {
                     for (int x = 0; x < 256 && success; ++x) {
                         int i = y * 256 + x;
                         REPORTER_ASSERT(reporter, success = pixels1[i] == pixels2[i]);
                     }
                 }
             }
         }
     }
 }