[webkit-help] Question about WebKit code in paintContents()

[hap 497]

HI,

In various WebKit code space, (e.g. Frame::markAllMatchesForText()), I
see it often calls
paintContents() like this:

   GraphicsContext context((PlatformGraphicsContext*)0);
   context.setPaintingDisabled(true);
   m_view->paintContents(&context, visibleRect);

What is the purpose of calling paintContents() when the
graphicsContext is set to paintingDisabled?