Currently upconverted characters (and string length) are computed twice in buildQuery() in DataDetection.mm:

    for (TextIterator iterator(contextRange); !iterator.atEnd(); iterator.advance(), iteratorCount++) {
        size_t currentTextLength = iterator.text().length();
        [...]
        const UniChar* currentCharPtr = iterator.text().upconvertedCharacters();
        [...]
        RetainPtr<CFStringRef> currentText = adoptCF(CFStringCreateWithCharacters(kCFAllocatorDefault, iterator.text().upconvertedCharacters(), iterator.text().length()));
        [...]
    }

<https://trac.webkit.org/browser/webkit/trunk/Source/WebCore/editing/cocoa/DataDetection.mm#L365>

There's no need to compute these twice, so we can extract the common code.

<rdar://problem/54689399>