Treat a GIF with no color table as transparent

third_party/gif/SkGifImageReader.cpp

Index: third_party/gif/SkGifImageReader.cpp
diff --git a/third_party/gif/SkGifImageReader.cpp b/third_party/gif/SkGifImageReader.cpp
index eeaee68c1d6a059f7aa020e14aff1e6a90a1964f..bbf5f9a2f0f41052eba9049aa0720c12531d657c 100644
--- a/third_party/gif/SkGifImageReader.cpp
+++ b/third_party/gif/SkGifImageReader.cpp
@@ -737,8 +737,10 @@ bool SkGifImageReader::parse(SkGifImageReader::SkGIFParseQuery query)
                 bool hasTransparentPixel;
                 if (m_frames.size() == 0) {
                     // We did not see a Graphics Control Extension, so no transparent
-                    // pixel was specified.
-                    hasTransparentPixel = false;
+                    // pixel was specified. But if there is no color table, this frame is
+                    // still transparent.
+                    hasTransparentPixel = !isLocalColormapDefined
+                                          && m_globalColorMap.numColors() == 0;
                 } else {
                     // This means we did see a Graphics Control Extension, which specifies
                     // the transparent pixel