Set scrollbar enabled state for overflow:auto.
PaintLayerScrollableArea code previously assumed it needed to setEnabled only
on scrollbars for overflow:scroll elements. This was because the only time we
would have a disabled scrollbar was for an overflow:scroll areas without enough
overflow. An overflow:auto area simply wouldn't have created the scrollbar.
This changes for overlay scrollbars because we fade out the scrollbars by
disabling them, causing painting code to avoid painting.
BUG=636392
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
Review-Url: https://codereview.chromium.org/2505253002
Cr-Commit-Position: refs/heads/master@{#433348}
5 files changed
