make allocPixels throw on failure

tests/BitmapHasherTest.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 "SkBitmapHasher.h"
 
 #include "SkBitmap.h"
 #include "SkColor.h"
 #include "Test.h"
 
 // Word size that is large enough to hold results of any checksum type.
 typedef uint64_t checksum_result;
 
 // Fill in bitmap with test data.
 static void CreateTestBitmap(SkBitmap* bitmap, int width, int height,
                              SkColor color, skiatest::Reporter* reporter) {
-    SkImageInfo info = SkImageInfo::MakeN32(width, height, kOpaque_SkAlphaType);
-    REPORTER_ASSERT(reporter, bitmap->allocPixels(info));
+    bitmap->allocN32Pixels(width, height, kOpaque_SkAlphaType);
     bitmap->eraseColor(color);
 }
 
 DEF_TEST(BitmapHasher, reporter) {
     // Test SkBitmapHasher
     SkBitmap bitmap;
     uint64_t digest;
     // initial test case
     CreateTestBitmap(&bitmap, 333, 555, SK_ColorBLUE, reporter);
     REPORTER_ASSERT(reporter, SkBitmapHasher::ComputeDigest(bitmap, &digest));
     REPORTER_ASSERT(reporter, digest == 0xfb2903562766ef87ULL);
     // same pixel data but different dimensions should yield a different checksum
     CreateTestBitmap(&bitmap, 555, 333, SK_ColorBLUE, reporter);
     REPORTER_ASSERT(reporter, SkBitmapHasher::ComputeDigest(bitmap, &digest));
     REPORTER_ASSERT(reporter, digest == 0xfe04023fb97d0f61ULL);
     // same dimensions but different color should yield a different checksum
     CreateTestBitmap(&bitmap, 555, 333, SK_ColorGREEN, reporter);
     REPORTER_ASSERT(reporter, SkBitmapHasher::ComputeDigest(bitmap, &digest));
     REPORTER_ASSERT(reporter, digest == 0x2423c51cad6d1edcULL);
 }