make allocPixels throw on failure

tests/KtxTest.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "Resources.h"
 #include "SkBitmap.h"
 #include "SkData.h"
@@ skipping 10 matching lines @@
 /**
  * First, make sure that writing an 8-bit RGBA KTX file and then
  * reading it produces the same bitmap.
  */
 DEF_TEST(KtxReadWrite, reporter) {
 
     // Random number generator with explicit seed for reproducibility
     SkRandom rand(0x1005cbad);
 
     SkBitmap bm8888;
-    bool pixelsAllocated = bm8888.allocN32Pixels(128, 128);
-    REPORTER_ASSERT(reporter, pixelsAllocated);
+    bm8888.allocN32Pixels(128, 128);
 
     uint8_t *pixels = reinterpret_cast<uint8_t*>(bm8888.getPixels());
     REPORTER_ASSERT(reporter, NULL != pixels);
 
     if (NULL == pixels) {
         return;
     }
     
     uint8_t *row = pixels;
     for (int y = 0; y < bm8888.height(); ++y) {        
@@ skipping 117 matching lines @@
     // Write the bitmap out to a KTX file.
     SkData *ktxDataPtr = SkImageEncoder::EncodeData(etcBitmap, SkImageEncoder::kKTX_Type, 0);
     SkAutoDataUnref newKtxData(ktxDataPtr);
     REPORTER_ASSERT(reporter, NULL != ktxDataPtr);
 
     // See is this data is identical to data in existing ktx file.
     SkString ktxFilename = GetResourcePath("mandrill_128.ktx");
     SkAutoDataUnref oldKtxData(SkData::NewFromFileName(ktxFilename.c_str()));
     REPORTER_ASSERT(reporter, oldKtxData->equals(newKtxData));
 }