Always use a color table with 256 colors

src/codec/SkGifCodec.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.
  */
 
 /*
  * Copyright (C) 2006 Apple Computer, Inc.  All rights reserved.
  *
@@ skipping 19 matching lines @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "SkCodecAnimation.h"
 #include "SkCodecPriv.h"
 #include "SkColorPriv.h"
 #include "SkColorTable.h"
 #include "SkGifCodec.h"
 #include "SkStream.h"
 #include "SkSwizzler.h"
+#include "SkUtils.h"
 
 #include <algorithm>
 
 #define GIF87_STAMP "GIF87a"
 #define GIF89_STAMP "GIF89a"
 #define GIF_STAMP_LEN 6
 
 /*
  * Checks the start of the stream to see if the image is a gif
  */
@@ skipping 86 matching lines @@
         result[i].fRequiredFrame = frameContext->getRequiredFrame();
     }
     return result;
 }
 
 void SkGifCodec::initializeColorTable(const SkImageInfo& dstInfo, size_t frameIndex,
         SkPMColor* inputColorPtr, int* inputColorCount) {
     fCurrColorTable = fReader->getColorTable(dstInfo.colorType(), frameIndex);
     fCurrColorTableIsReal = fCurrColorTable;
     if (!fCurrColorTable) {
-        // This is possible for an empty frame. Create a dummy with one value (transparent).
-        SkPMColor color = SK_ColorTRANSPARENT;
-        fCurrColorTable.reset(new SkColorTable(&color, 1));
+        // This is possible for an empty frame. Create a dummy with all transparent.
+        SkPMColor colors[MAX_COLORS];
+        sk_memset32(colors, SK_ColorTRANSPARENT, MAX_COLORS);
+        fCurrColorTable.reset(new SkColorTable(colors, 256));
     }
 
     if (inputColorCount) {
         *inputColorCount = fCurrColorTable->count();
     }
 
     copy_color_table(dstInfo, fCurrColorTable.get(), inputColorPtr, inputColorCount);
 }
 
 
@@ skipping 397 matching lines @@
         void* copiedLine = SkTAddOffset<void>(dstLine, fSwizzler->swizzleOffsetBytes());
         void* dst = copiedLine;
         for (unsigned i = 1; i < repeatCount; i++) {
             dst = SkTAddOffset<void>(dst, fDstRowBytes);
             memcpy(dst, copiedLine, bytesToCopy);
         }
     }
 
     return true;
 }