This reverts commit 13040043b2.
It introduced a bad regression, noticeable for longer documents, as
it would cause the documentChanged(0, length) to trigger a layout of
the entire document.
The bug report for the commit (or the commit itself) does not contain
a test case, but it is regardless the wrong approach. Note that
QQuickTextEdit already listens to the contentsChange signal and
invalidates the changed parts of the document as a reaction to this,
so it should already work as expected.
[ChangeLog][Qt Gui][Text] Fixed performance hit from showing large
QTextDocuments in a QTextEdit or QTextBrowser. (Regression introduced
in Qt 5.3.0)
Task-number: QTBUG-51411
Change-Id: I6e7fbf8f62a1d68779eef5da3781de14d9fdcad8
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>
