GIF: Fill the frame if we have a dummy color table

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 280 matching lines @@
             // We may need to clear to transparent for one of the following reasons:
             // - The frameRect does not cover the full bounds. haveDecodedRow will
             //   only draw inside the frameRect, so we need to clear the rest.
             // - There is a valid transparent pixel value. (FIXME: I'm assuming
             //   writeTransparentPixels will be false in this case, based on
             //   Chromium's assumption that it would already be zeroed. If we
             //   change that behavior, could we skip Filling here?)
             // - The frame is interlaced. There is no obvious way to fill
             //   afterwards for an incomplete image. (FIXME: Does the first pass
             //   cover all rows? If so, we do not have to fill here.)
+            // - There is no color table for this frame. In that case will not
+            //   draw anything, so we need to fill.
             if (frameContext->frameRect() != this->getInfo().bounds()
                     || frameContext->transparentPixel() < SK_MAX_COLORS
-                    || frameContext->interlaced()) {
+                    || frameContext->interlaced() || !fCurrColorTableIsReal) {
                 // fill ignores the width (replaces it with the actual, scaled width).
                 // But we need to scale in Y.
                 const int scaledHeight = get_scaled_dimension(dstInfo.height(),
                                                               fSwizzler->sampleY());
                 auto fillInfo = dstInfo.makeWH(0, scaledHeight);
                 fSwizzler->fill(fillInfo, fDst, fDstRowBytes, this->getFillValue(dstInfo),
                                 opts.fZeroInitialized);
                 filledBackground = true;
             }
         } else {
@@ skipping 240 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;
 }