substring         554 Source/core/editing/TextIterator.cpp String TextIterator::substring(unsigned position, unsigned length) const
substring        1710 Source/core/editing/TextIterator.cpp String WordAwareIterator::substring(unsigned position, unsigned length) const
substring         472 Source/wtf/text/StringImpl.cpp PassRefPtr<StringImpl> StringImpl::substring(unsigned start, unsigned length)
substring         345 Source/wtf/text/WTFString.cpp String String::substring(unsigned pos, unsigned len) const