Created attachment 8691466 [details] [diff] [review] WIP In bug 1223928 I enabled the Gecko scrollbars for Fennec with C++ APZ, but at around the same time some theming changes landed in bug 1223526 which made it not work again. In particular there appear to be some styles that we used to be pulling in from toolkit/themes/windows/global/xulscrollbars.css that we are no longer doing, and that is causing the scrollbars to not show up. I was under the impression that all the relevant styles were already in mobile/android/themes/core/content.css but that's not the case, apparently. The attached WIP does fix the scrollbars by copying the windows scrollbar styles back into the mobile theme, but it's probably overkill to take all those styles when we're probably just missing a couple. I suspect a better approach would be to take the scrollbar-related styles from content.css, merge them with the windows scrollbar styles, throw out anything that's not needed, and save the rest into a new override file in mobile/android/themes/core. However my knowledge of the theming/packaging of this stuff is almost nil so I don't know if that even makes sense.
Created attachment 8691485 [details] [diff] [review] Patch Looks like it was just a few missing properties. Putting those into content.css fixes the issue.
Comment on attachment 8691485 [details] [diff] [review] Patch Nice!