RESOLVED DUPLICATE of bug 63499 78943
Avoid compositing empty elements 
https://bugs.webkit.org/show_bug.cgi?id=78943
Summary Avoid compositing empty elements
Xianzhu Wang
Reported 2012-02-17 16:20:32 PST
Google+ has a zero-height fixed-position element beneath the main content. we enable compositing for fixed-position elements, which means lots of content divs overlap it and are also composited. -- husky@chromium.org
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Xianzhu Wang
Comment 1 2012-02-23 11:15:45 PST
Just verified that the patch of bug 78186 also fixed this bug, because an empty rect doesn't intersect any other rect.
Xianzhu Wang
Comment 2 2012-02-23 15:59:46 PST
Sorry my previous verification was not complete. Bug 78186 can prevents empty fixed position element that is at the bottom layer from being composited (and in turn may prevent elements over it from being composited). If an empty element is over another composited element, it may still be composited because the intersect condition change in bug 34065. Would it be better to fix issue of cliprect cache instead of changing the overlap checking for bug 34065 that will cause unnecessary compositing layers? We also tried to disable cliprect cache, and didn't see visible performance change.
Xianzhu Wang
Comment 3 2012-03-14 14:32:46 PDT
*** This bug has been marked as a duplicate of bug 63499 ***
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