2009-06-12  David Levin  <levin@chromium.org>

        Reviewed by Darin Adler.

        UString shouldn't create sharedBuffer for SmallStrings.
        https://bugs.webkit.org/show_bug.cgi?id=26360

        The methods changed are not used by JSC, so there is no JS perf impact.  However,
        there is a potential DOM perf impact, so I re-ran several of the tests that
        I ran previously and ensured that the perf stay the same which caused me to
        adjust the minLengthToShare.

        * JavaScriptCore.exp:
        * runtime/UString.cpp:
        (JSC::UString::Rep::sharedBuffer):
            Determines if the buffer being shared is big enough before doing so.
            Previously, BaseString::sharedBuffer was called but it would only know
            the length of the base string (BaseString::len) which may not be the same
            as the string being shared (Rep::len).
        (JSC::UString::BaseString::sharedBuffer):
            This is now only be used by Rep::sharedBuffer. which does the length check.
        * runtime/UString.h:

WebCore:

2009-06-12  David Levin  <levin@chromium.org>

        Reviewed by Darin Adler.

        UString shouldn't create sharedBuffer for SmallStrings.
        https://bugs.webkit.org/show_bug.cgi?id=26347

        Change the call to use the method UString::Rep::sharedBuffer due
        to changes in UString.

        No noticable change in behavior, so no test.

        * platform/text/StringImpl.cpp:
        (WebCore::StringImpl::create):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@44641 268f45cc-cd09-0410-ab3c-d52691b4dbfc