http://test-results.appspot.com/dashboards/flakiness_dashboard.html#tests=platform%2Fchromium%2Fcompositing%2Frubberbanding%2Ftransform-overhang-nw.html%2Cplatform%2Fchromium%2Fcompositing%2Frubberbanding%2Ftransform-overhang-sw.html%2Cplatform%2Fchromium%2Fcompositing%2Frubberbanding%2Ftransform-overhang-n.html%2Cplatform%2Fchromium%2Fcompositing%2Frubberbanding%2Ftransform-overhang-ne.html%2Cplatform%2Fchromium%2Fcompositing%2Frubberbanding%2Ftransform-overhang-size-change.html%2Cplatform%2Fchromium%2Fcompositing%2Frubberbanding%2Ftransform-overhang-w.html There has been a lot of test flipping that makes it hard for me to tell what caused the most recent failure. According to the flakiness dashboard, the regression is in this range: http://trac.webkit.org/log/?verbose=on&rev=107345&stop_rev=107313 The most likely change is http://trac.webkit.org/changeset/107335/ or http://trac.webkit.org/changeset/107329/ .
James can you take a look? I'm going to mark the tests as failing for now.
See also bug 78008.
Looking at the flaky runs of green/non-green results, the non-green results have tiny pixel differences in the rubber band gradients only. Is that a known cause of flakyness with the compositing path? It seems the non-compositing rubber-banding tests don't have this flakyness in the gradients. And then there's the more recent regression that just causes them to fail all the time due to not pattern/gradient area being drawn at all...
Pretty sure it's the mock scrollbars change. Rubber-band overhang painting is done by ScrollbarThemeChromiumMac.mm, while the mock scrollbar changes replaces this by ScrollbarThemeMock.
Created attachment 127389 [details] Patch
Comment on attachment 127389 [details] Patch If you want these specific tests to not use mock scrollbars, then just call window.internals.settings.setMockScrollbarsEnabled(false) in the tests
Created attachment 127415 [details] Patch
Comment on attachment 127415 [details] Patch New patch that just changes the tests to disable mock scrollbars.
Comment on attachment 127415 [details] Patch r=me
Comment on attachment 127415 [details] Patch Clearing flags on attachment: 127415 Committed r108000: <http://trac.webkit.org/changeset/108000>
All reviewed patches have been landed. Closing bug.