Consider merging https://chromium.googlesource.com/chromium/blink/+/cd68b8af13f894be2a69b0a886781d8f8d7cb17f http://whatwg.org/html#htmlappletelement In addition to removing TreatNullAs=NullString, align with the spec by making hspace/vspace unsigned long, and codebase/object URLs. The tests for the updated properties pass in Firefox Nightly, IE11 Release Preview and Opera 12.16, with these exceptions: IE11 returns "" after setting width/height to null and fails all of the vspace/hspace reflection tests in ways not per spec. Presto doesn't reflect object as a URL, but the framework didn't notice that before the minor fix in nullTestElementAttribute. Presto also fails the vspace/hspace set tests in ways not per spec.
Mass closing plug-in bugs, as plug-in support has been removed from WebKit. Please comment and/or reopen if this still affects WebKit in some way.