Brought up in https://codereview.chromium.org/2565323003/diff/2140001/third_party/WebKit/Source/platform/image-decoders/gif/GIFImageDecoder.cpp#newcode257

BitmapImage attempts to avoid showing partial frames by calling FrameIsCompleteAtIndex, but that only prevents showing a frame that hasn't received all the data for that frame. If there is an error in the data, I suspect we'll still see a torn frame.

(We will correctly call SetFailed, preventing us from continuing to try to decode, but I believe we'll still show that final frame.)