Merge changes I8da1b801,Id88446d6,I82798d5a

* changes:
  Merge Webkit at r58956: Update User agent with new WebKit version.
  Merge Webkit at r58956: Update DRT FileFilter.
  Merge Webkit at r58956: Plugin code has switched to C99 integer types. See http://trac.webkit.org/changeset/58590