Fix codec memory leaks in nanobench

bench/subset/SubsetTranslateBench.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "CodecBenchPriv.h"
 #include "SubsetTranslateBench.h"
 #include "SubsetBenchPriv.h"
@@ skipping 122 matching lines @@
                             // two used by the subsets we care about. skbug.com/4428
                             SkASSERT(false);
                     }
                 }
             }
         }
     } else {
         // We create a color table here to satisfy allocPixels() when the output
         // type is kIndex8.  It's okay that this is uninitialized since we never
         // use it.
-        SkColorTable* colorTable = new SkColorTable(colors, 0);
+        SkAutoTUnref<SkColorTable> colorTable(new SkColorTable(colors, 0));
         for (int count = 0; count < n; count++) {
             int width, height;
             SkAutoTDelete<SkImageDecoder> decoder(SkImageDecoder::Factory(fStream));
             SkAssertResult(decoder->buildTileIndex(fStream->duplicate(), &width, &height));
             SkBitmap bitmap;
             // Note that we use the same bitmap for all of the subsets.
             // It might be larger than necessary for the end subsets.
             // If we do not include this step, decodeSubset() would allocate space
             // for the pixels automatically, but this would not allow us to reuse the
             // same bitmap as the other subsets.  We want to reuse the same bitmap
             // because it gives a more fair comparison with SkCodec and is a common
             // use case of BitmapRegionDecoder.
             bitmap.allocPixels(SkImageInfo::Make(fSubsetWidth, fSubsetHeight,
                     fColorType, kOpaque_SkAlphaType), nullptr, colorTable);
 
             for (int x = 0; x < width; x += fSubsetWidth) {
                 for (int y = 0; y < height; y += fSubsetHeight) {
                     const uint32_t currSubsetWidth = x + (int) fSubsetWidth > width ?
                             width - x : fSubsetWidth;
                     const uint32_t currSubsetHeight = y + (int) fSubsetHeight > height ?
                             height - y : fSubsetHeight;
                     SkIRect rect = SkIRect::MakeXYWH(x, y, currSubsetWidth,
                             currSubsetHeight);
                     SkAssertResult(decoder->decodeSubset(&bitmap, rect, fColorType));
                 }
             }
         }
     }
 }