Fix codec memory leaks in nanobench

bench/subset/SubsetTranslateBench.cpp

Index: bench/subset/SubsetTranslateBench.cpp
diff --git a/bench/subset/SubsetTranslateBench.cpp b/bench/subset/SubsetTranslateBench.cpp
index f6f3d4b22290998a11e4881addae2ee5239b8b2c..27c628edde6c1c305241fff34b5cbc8979c5153b 100644
--- a/bench/subset/SubsetTranslateBench.cpp
+++ b/bench/subset/SubsetTranslateBench.cpp
@@ -140,7 +140,7 @@ void SubsetTranslateBench::onDraw(int n, SkCanvas* canvas) {
         // 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));