The QImageReader::loopCount was wrong until recently for non animated gifs but that was fixed in Qt4.7. We will need the loopCount of Qt to WebCore.
Created attachment 50374 [details]
Make non-animated gifs' non-animated.
Attachment 50374 [details] did not pass style-queue:
Failed to run "WebKitTools/Scripts/check-webkit-style" exit_code: 1
WebCore/platform/graphics/qt/ImageDecoderQt.cpp:130: Tests for true/false, null/non-null, and zero/non-zero should all be done without equality comparisons. [readability/comparison_to_zero] 
Total errors found: 1 in 5 files
If any of these errors are false positives, please file a bug against check-webkit-style.
Landed in r55774.