In r182673 nightly, String.prototype.startsWith and String.prototype.endsWith both have a length of 0. According to https://people.mozilla.org/~jorendorff/es6-draft.html#sec-string.prototype.startswith and https://people.mozilla.org/~jorendorff/es6-draft.html#sec-string.prototype.endswith the length of both should explicitly be 1, since they have 1 required argument.
*** Bug 143660 has been marked as a duplicate of this bug. ***
Created attachment 250881 [details] Patch
Comment on attachment 250881 [details] Patch Clearing flags on attachment: 250881 Committed r182872: <http://trac.webkit.org/changeset/182872>
All reviewed patches have been landed. Closing bug.