commit 3f34d9380173cbb2b36d76a859a477472e80ae61
author skobes <skobes@chromium.org> Sat Oct 22 05:02:33 2016
committer Commit bot <commit-bot@chromium.org> Sat Oct 22 05:04:37 2016
tree d7ae81d3390befad2dafa677ff89def6ca5fc7ab
parent 41176b1fbb13e3c55f60b35ccdb74a5f501e0960

Fix unscrollable scrollers after closing a <dialog>.

Inertness of a scroller can change without causing it to be laid out, if a
dialog is added or removed from Document::m_topLayerElements.  Checking
inertness in PLSA::updateScrollableAreaSet led to stale compositing state.

This patch updates PLSA to ignore inertness.  This means scrollers will remain
in FrameView::m_scrollableAreas even when covered by a dialog.  That should be
ok, since the ::backdrop element prevents them from actually receiving input.

BUG=633520
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2

Review-Url: https://chromiumcodereview.appspot.com/2437303002
Cr-Commit-Position: refs/heads/master@{#426975}