SubtreeVisibility: Ensure that paint layers don't recurse into locked trees.

This patch ensures that we don't recurse into paint layers that have
display locked subtrees. We need to do this since the subtrees don't paint
and might not have up-to-date layout information, which is needed to
calculate their rects.

R=chrishtr@chromium.org

Fixed: 1059330
Change-Id: I832dfed1a47fba090c6e3ddd92de1846a47c3f98
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2091599Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
Commit-Queue: vmpstr <vmpstr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#747879}

third_party/blink/renderer/core/paint/paint_layer.cc

@@ -2711,6 +2711,14 @@ void PaintLayer::ExpandRectForStackingChildren(
     const PaintLayer& composited_layer,
     PhysicalRect& result,
     PaintLayer::CalculateBoundsOptions options) const {
+  // If we're locked, th en the subtree does not contribute painted output.
+  // Furthermore, we might not have up-to-date sizing and position information
+  // in the subtree, so skip recursing into the subtree.
+  if (GetLayoutObject().PaintBlockedByDisplayLock(
+          DisplayLockLifecycleTarget::kChildren)) {
+    return;
+  }
+
   PaintLayerPaintOrderIterator iterator(*this, kAllChildren);
   while (PaintLayer* child_layer = iterator.Next()) {
     // Here we exclude both directly composited layers and squashing layers

third_party/blink/web_tests/TestExpectations

@@ -183,7 +183,6 @@ crbug.com/807395 fast/multicol/mixed-opacity-test.html [ Failure ]
 
 ########## display-lock failures ##########
 wpt_internal/display-lock/css-subtree-visibility/subtree-visibility-047.html [ Failure ]
-wpt_internal/display-lock/css-subtree-visibility/subtree-visibility-008.html [ Pass Failure Crash ]
 
 ########## Ref tests can't be rebaselined ##########
 crbug.com/504613 crbug.com/524248 [ Mac ] paint/images/image-backgrounds-not-antialiased.html [ Failure ]