Only delay tab suspension when the main frame title changes, not subframes' titles. The reason we do this is because the main frame title shows in the tab label and the tab may communicate useful information this way, even when backgrounded.
Pull request: https://github.com/WebKit/WebKit/pull/13368
Committed 263605@main (03e5627ae89f): <https://commits.webkit.org/263605@main> Reviewed commits have been landed. Closing PR #13368 and removing active labels.
<rdar://problem/108808940>