After r139189, pixel alignment is performed in UI units. If deviceScaleFactor is fractional number, adjusted scroll position can blur non-composited layer.
Created attachment 182016 [details] Patch
Comment on attachment 182016 [details] Patch View in context: https://bugs.webkit.org/attachment.cgi?id=182016&action=review > Source/WebKit2/UIProcess/PageViewportController.cpp:98 > + float contentsScale = m_pageScaleFactor * deviceScaleFactor(); lets call this effectiveScale
Created attachment 182082 [details] Patch
Comment on attachment 182082 [details] Patch Clearing flags on attachment: 182082 Committed r139300: <http://trac.webkit.org/changeset/139300>
All reviewed patches have been landed. Closing bug.