Optimize LocalFrameView::incrementVisuallyNonEmptyCharacterCount().
Pull request: https://github.com/WebKit/WebKit/pull/18411
Committed 268659@main (38d1d72e3b8a): <https://commits.webkit.org/268659@main> Reviewed commits have been landed. Closing PR #18411 and removing active labels.
<rdar://problem/116245782>