Implement Fill() for incomplete decodes to RGBA_F16

src/codec/SkGifCodec.cpp

Index: src/codec/SkGifCodec.cpp
diff --git a/src/codec/SkGifCodec.cpp b/src/codec/SkGifCodec.cpp
index 1e6e300a9233ec8e24d45c392b877b291154d565..c35cd24ae498f5d12f62c39a687a95a57b9fcb08 100644
--- a/src/codec/SkGifCodec.cpp
+++ b/src/codec/SkGifCodec.cpp
@@ -494,7 +494,7 @@ SkCodec::Result SkGifCodec::onGetPixels(const SkImageInfo& dstInfo,
     // Initialize the swizzler
     if (fFrameIsSubset) {
         // Fill the background
-        SkSampler::Fill(dstInfo, dst, dstRowBytes, this->getFillValue(dstInfo.colorType()),
+        SkSampler::Fill(dstInfo, dst, dstRowBytes, this->getFillValue(dstInfo),
                 opts.fZeroInitialized);
     }
 
@@ -512,9 +512,10 @@ SkCodec::Result SkGifCodec::onGetPixels(const SkImageInfo& dstInfo,
 
 // FIXME: This is similar to the implementation for bmp and png.  Can we share more code or
 //        possibly make this non-virtual?
-uint32_t SkGifCodec::onGetFillValue(SkColorType colorType) const {
+uint64_t SkGifCodec::onGetFillValue(const SkImageInfo& dstInfo) const {
     const SkPMColor* colorPtr = get_color_ptr(fColorTable.get());
-    return get_color_table_fill_value(colorType, colorPtr, fFillIndex);
+    return get_color_table_fill_value(dstInfo.colorType(), dstInfo.alphaType(), colorPtr,
+                                      fFillIndex, nullptr);
 }
 
 SkCodec::Result SkGifCodec::onStartScanlineDecode(const SkImageInfo& dstInfo,
@@ -555,7 +556,7 @@ int SkGifCodec::onGetScanlines(void* dst, int count, size_t rowBytes) {
     if (fFrameIsSubset) {
         // Fill the requested rows
         SkImageInfo fillInfo = this->dstInfo().makeWH(this->dstInfo().width(), count);
-        uint32_t fillValue = this->onGetFillValue(this->dstInfo().colorType());
+        uint64_t fillValue = this->onGetFillValue(this->dstInfo());
         fSwizzler->fill(fillInfo, dst, rowBytes, fillValue, this->options().fZeroInitialized);
 
         // Start to write pixels at the start of the image frame