Like the other experimental constructors exposed from DOMWindow, the WebGLArray constructors should have the EnabledAtRuntime attribute specified.
Chromium side of this bug is http://code.google.com/p/chromium/issues/detail?id=37098 .
Created attachment 49770 [details] Patch
Comment on attachment 49770 [details] Patch Clearing flags on attachment: 49770 Committed r55419: <http://trac.webkit.org/changeset/55419>
All reviewed patches have been landed. Closing bug.