Fix CodecSubset benches seg faults for kIndex8

bench/subset/SubsetZoomBench.cpp

Index: bench/subset/SubsetZoomBench.cpp
diff --git a/bench/subset/SubsetZoomBench.cpp b/bench/subset/SubsetZoomBench.cpp
index 3ce193b6ea8da33e7083da2c1e3386ea58ac2114..896da89a150a53485e1f5eb109de0398f5c14038 100644
--- a/bench/subset/SubsetZoomBench.cpp
+++ b/bench/subset/SubsetZoomBench.cpp
@@ -55,7 +55,7 @@ bool SubsetZoomBench::isSuitableFor(Backend backend) {
 void SubsetZoomBench::onDraw(const int n, SkCanvas* canvas) {
     // When the color type is kIndex8, we will need to store the color table.  If it is
     // used, it will be initialized by the codec.
-    int colorCount;
+    int colorCount = 0;
     SkPMColor colors[256];
     if (fUseCodec) {
         for (int count = 0; count < n; count++) {
@@ -77,7 +77,8 @@ void SubsetZoomBench::onDraw(const int n, SkCanvas* canvas) {
                 // Note that if we subsetted and scaled in a single step, we could use the
                 // same bitmap - as is often done in actual use cases.
                 SkBitmap bitmap;
-                bitmap.allocPixels(info.makeWH(subsetWidth, subsetHeight));
+                bitmap.allocPixels(info.makeWH(subsetWidth, subsetHeight), NULL,
+                        SkNEW_ARGS(SkColorTable, (colors, colorCount)));
 
                 uint32_t bpp = info.bytesPerPixel();
                 scanlineDecoder->skipScanlines(subsetStartY);