4 files changed, 21 insertions, 23 deletions

diff --git a/resources/colorTables.gif b/resources/colorTables.gif
new file mode 100644
index 0000000000..f25d13cfaa
--- /dev/null
+++ b/resources/colorTables.gif
diff --git a/src/codec/SkGifCodec.cpp b/src/codec/SkGifCodec.cpp
index fe0a2b6623..13223960c8 100644
--- a/src/codec/SkGifCodec.cpp
+++ b/src/codec/SkGifCodec.cpp
@@ -139,8 +139,7 @@ std::vector<SkCodec::FrameInfo> SkGifCodec::onGetFrameInfo() {
     return result;
 }
 
-void SkGifCodec::initializeColorTable(const SkImageInfo& dstInfo, size_t frameIndex,
-        SkPMColor* inputColorPtr, int* inputColorCount) {
+void SkGifCodec::initializeColorTable(const SkImageInfo& dstInfo, size_t frameIndex) {
     fCurrColorTable = fReader->getColorTable(dstInfo.colorType(), frameIndex);
     fCurrColorTableIsReal = fCurrColorTable;
     if (!fCurrColorTable) {
@@ -148,12 +147,6 @@ void SkGifCodec::initializeColorTable(const SkImageInfo& dstInfo, size_t frameIn
         SkPMColor color = SK_ColorTRANSPARENT;
         fCurrColorTable.reset(new SkColorTable(&color, 1));
     }
-
-    if (inputColorCount) {
-        *inputColorCount = fCurrColorTable->count();
-    }
-
-    copy_color_table(dstInfo, fCurrColorTable.get(), inputColorPtr, inputColorCount);
 }
 
 
@@ -215,9 +208,15 @@ SkCodec::Result SkGifCodec::prepareToDecode(const SkImageInfo& dstInfo, SkPMColo
 
     fTmpBuffer.reset(new uint8_t[dstInfo.minRowBytes()]);
 
-    // Initialize color table and copy to the client if necessary
-    this->initializeColorTable(dstInfo, frameIndex, inputColorPtr, inputColorCount);
+    this->initializeColorTable(dstInfo, frameIndex);
     this->initializeSwizzler(dstInfo, frameIndex);
+
+    SkASSERT(fCurrColorTable);
+    if (inputColorCount) {
+        *inputColorCount = fCurrColorTable->count();
+    }
+    copy_color_table(dstInfo, fCurrColorTable.get(), inputColorPtr, inputColorCount);
+
     return kSuccess;
 }
 
@@ -337,6 +336,11 @@ SkCodec::Result SkGifCodec::decodeFrame(bool firstAttempt, const Options& opts,
                 Options prevFrameOpts(opts);
                 prevFrameOpts.fFrameIndex = frameContext->getRequiredFrame();
                 prevFrameOpts.fHasPriorFrame = false;
+                // The prior frame may have a different color table, so update it and the
+                // swizzler.
+                this->initializeColorTable(dstInfo, prevFrameOpts.fFrameIndex);
+                this->initializeSwizzler(dstInfo, prevFrameOpts.fFrameIndex);
+
                 const Result prevResult = this->decodeFrame(true, prevFrameOpts, nullptr);
                 switch (prevResult) {
                     case kSuccess:
@@ -348,6 +352,10 @@ SkCodec::Result SkGifCodec::decodeFrame(bool firstAttempt, const Options& opts,
                     default:
                         return prevResult;
                 }
+
+                // Go back to using the correct color table for this frame.
+                this->initializeColorTable(dstInfo, frameIndex);
+                this->initializeSwizzler(dstInfo, frameIndex);
             }
             const auto* prevFrame = fReader->frameContext(frameContext->getRequiredFrame());
             if (prevFrame->getDisposalMethod() == SkCodecAnimation::RestoreBGColor_DisposalMethod) {
diff --git a/src/codec/SkGifCodec.h b/src/codec/SkGifCodec.h
index b5f8f7ce0c..9d8e0e46bf 100644
--- a/src/codec/SkGifCodec.h
+++ b/src/codec/SkGifCodec.h
@@ -62,19 +62,8 @@ private:
      *
      * @param dstInfo         Contains the requested dst color type.
      * @param frameIndex      Frame whose color table to use.
-     * @param inputColorPtr   Copies the encoded color table to the client's
-     *                        input color table if the client requests kIndex8.
-     * @param inputColorCount If the client requests kIndex8, this will be set
-     *                        to the number of colors in the array that
-     *                        inputColorPtr now points to. This will typically
-     *                        be 256. Since gifs may have up to 8-bit indices,
-     *                        using a 256-entry table means a pixel will never
-     *                        be out of range. This will be set to 1 if there
-     *                        is no color table, since that will be a
-     *                        transparent frame.
      */
-    void initializeColorTable(const SkImageInfo& dstInfo, size_t frameIndex,
-            SkPMColor* colorPtr, int* inputColorCount);
+    void initializeColorTable(const SkImageInfo& dstInfo, size_t frameIndex);
 
    /*
     * Does necessary setup, including setting up the color table and swizzler,
diff --git a/tests/CodecAnimTest.cpp b/tests/CodecAnimTest.cpp
index fee6879a90..de36ce65d0 100644
--- a/tests/CodecAnimTest.cpp
+++ b/tests/CodecAnimTest.cpp
@@ -29,6 +29,7 @@ DEF_TEST(Codec_frames, r) {
         { "box.gif", 1, {}, {} },
         { "color_wheel.gif", 1, {}, {} },
         { "test640x479.gif", 4, { 0, 1, 2 }, { 200, 200, 200, 200 } },
+        { "colorTables.gif", 2, { 0 }, { 1000, 1000 } },
 
         { "arrow.png",  1, {}, {} },
         { "google_chrome.ico", 1, {}, {} },
@@ -67,7 +68,7 @@ DEF_TEST(Codec_frames, r) {
 
         if (rec.fRequiredFrames.size() + 1 != expected) {
             ERRORF(r, "'%s' has wrong number entries in fRequiredFrames; expected: %i\tactual: %i",
-                   rec.fName, expected, rec.fRequiredFrames.size());
+                   rec.fName, expected, rec.fRequiredFrames.size() + 1);
             continue;
         }