make allocPixels throw on failure

tests/SkResourceCacheTest.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 "Test.h"
 #include "SkCanvas.h"
 #include "SkGraphics.h"
 #include "SkBitmapCache.h"
 
 static const int kCanvasSize = 1;
 static const int kBitmapSize = 16;
 static const int kScale = 8;
 
 static bool is_in_scaled_image_cache(const SkBitmap& orig,
                                      SkScalar xScale,
                                      SkScalar yScale) {
     SkBitmap scaled;
     float roundedImageWidth = SkScalarRoundToScalar(orig.width() * xScale);
     float roundedImageHeight = SkScalarRoundToScalar(orig.height() * xScale);
     return SkBitmapCache::Find(orig, roundedImageWidth, roundedImageHeight, &scaled);
 }
 
 // Draw a scaled bitmap, then return true iff it has been cached.
 static bool test_scaled_image_cache_useage() {
     SkAutoTUnref<SkCanvas> canvas(
             SkCanvas::NewRasterN32(kCanvasSize, kCanvasSize));
     SkBitmap bitmap;
-    SkAssertResult(bitmap.allocN32Pixels(kBitmapSize, kBitmapSize));
+    bitmap.allocN32Pixels(kBitmapSize, kBitmapSize);
     bitmap.eraseColor(0xFFFFFFFF);
     SkScalar scale = SkIntToScalar(kScale);
     SkScalar scaledSize = SkIntToScalar(kBitmapSize) * scale;
     canvas->clipRect(SkRect::MakeLTRB(0, 0, scaledSize, scaledSize));
     SkPaint paint;
     paint.setFilterLevel(SkPaint::kHigh_FilterLevel);
 
     canvas->drawBitmapRect(bitmap,
                            SkRect::MakeLTRB(0, 0, scaledSize, scaledSize),
                            &paint);
@@ skipping 24 matching lines @@
 
     SkGraphics::SetResourceCacheTotalByteLimit(0);  // clear cache
     SkGraphics::SetResourceCacheTotalByteLimit(2 * size);
     SkGraphics::SetResourceCacheSingleAllocationByteLimit(size / 2);  // too small
 
     REPORTER_ASSERT(reporter, !test_scaled_image_cache_useage());
 
     SkGraphics::SetResourceCacheSingleAllocationByteLimit(originalAllocationLimit);
     SkGraphics::SetResourceCacheTotalByteLimit(originalByteLimit);
 }