WebKit1's WebView sometimes does some extra work when a layout-before-paint puts the page into accelerated compositing mode

• Component: Layout and Rendering
• Status: NEW ---

[Adam Roben (:aroben)]

Whenever WebView is about to paint, it first does a layout to ensure it's painting up-to-date bits. This layout can put the page into accelerated compositing mode. But WebView doesn't detect that this has happened, and goes ahead and finishes the paint anyway, even though the painted bits will never be seen (since now rendering is being taken care of by the layer tree host).

It would be somewhat more efficient for WebView to detect that this has happened and bail out of the paint.