<rdar://problem/5757873> Buffer overrun in DeprecatedCString::find() in WebCore

    <rdar://problem/5757873> Buffer overrun in DeprecatedCString::find() in WebCore
        We could get a buffer overrun in DeprecatedCString::find() if the end of the
        string matches a beginning portion of the substring, for example, if string is
        "a" but the substring is "ab".
        The code as is also will not match things correctly under certain situations
        since the inner while loop increments the index. For example, we wouldn't find
        a match if the string is "aab..." and the substring is "ab".  Changed the
        inner while loop to increment a temporary index into str.

        Test: fast/loader/charset-parse.html

        Reviewed by Dan Berstein.

        * platform/DeprecatedCString.cpp:
        (WebCore::DeprecatedCString::find):

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@30468 268f45cc-cd09-0410-ab3c-d52691b4dbfc