Change DCHECK in UpdateStyleAndLayoutTreeForNode to check !InStyleRecalc()

UpdateStyleAndLayoutTreeForNode should not be called from within a normal lifecycle update because it also updates things in display locked subtrees - it should only be called for forced style calculations. However, scripts that do forced style calculations might actually run from within a lifecycle update (for example, in a ResizeObserver callback), hitting the DCHECK. As there's no easy way to differentiate the cases, we're changing DCHECK in this CL to just check that we're not in style recalc phase of the lifecycle update. Bug: 963062 Change-Id: Ib3692960b008043057b27180f57447966e6127e3 Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1614337Reviewed-by: Kent Tamura <tkent@chromium.org> Reviewed-by: vmpstr <vmpstr@chromium.org> Commit-Queue: Rakina Zata Amni <rakina@chromium.org> Cr-Commit-Position: refs/heads/master@{#660729}

Change DCHECK in UpdateStyleAndLayoutTreeForNode to check !InStyleRecalc()
UpdateStyleAndLayoutTreeForNode should not be called from within a normal lifecycle update because it also updates things in display locked subtrees - it should only be called for forced style calculations. However, scripts that do forced style calculations might actually run from within a lifecycle update (for example, in a ResizeObserver callback), hitting the DCHECK. As there's no easy way to differentiate the cases, we're changing DCHECK in this CL to just check that we're not in style recalc phase of the lifecycle update. Bug: 963062 Change-Id: Ib3692960b008043057b27180f57447966e6127e3 Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1614337Reviewed-by: Kent Tamura <tkent@chromium.org> Reviewed-by: vmpstr <vmpstr@chromium.org> Commit-Queue: Rakina Zata Amni <rakina@chromium.org> Cr-Commit-Position: refs/heads/master@{#660729}
bbce3cdc · Rakina Zata Amni · Commit Bot · 8dde0a59 · bbce3cdc · bbce3cdc
Commit bbce3cdc authored May 17, 2019 by Rakina Zata Amni Committed by Commit Bot May 17, 2019
3 changed files
--- a/third_party/blink/renderer/core/dom/document.cc
+++ b/third_party/blink/renderer/core/dom/document.cc
@@ -2468,13 +2468,8 @@ void Document::UpdateStyleAndLayoutTreeForNode(const Node* node) {
    DCHECK_EQ(node->ownerDocument(), this);
    return;
  }
-  DCHECK(node->GetDocument().GetPage());
-  DCHECK(!node->GetDocument()
-              .GetPage()
-              ->Animator()
-              .UpdatingLayoutAndStyleForPainting())
-      << "UpdateStyleAndLayoutTreeForNode called from within a lifecycle "
-         "update";
+  DCHECK(!InStyleRecalc())
+      << "UpdateStyleAndLayoutTreeForNode called from within style recalc";
  if (!NeedsLayoutTreeUpdateForNodeIncludingDisplayLocked(*node))
    return;


--- a/third_party/blink/renderer/core/page/page_animator.h
+++ b/third_party/blink/renderer/core/page/page_animator.h
@@ -40,9 +40,6 @@ class CORE_EXPORT PageAnimator final : public GarbageCollected<PageAnimator> {
  void UpdateAllLifecyclePhasesExceptPaint(LocalFrame& root_frame);
  void UpdateLifecycleToLayoutClean(LocalFrame& root_frame);
  AnimationClock& Clock() { return animation_clock_; }
-  bool UpdatingLayoutAndStyleForPainting() {
-    return updating_layout_and_style_for_painting_;
-  }

 private:
  Member<Page> page_;

--- a/third_party/blink/web_tests/resize-observer/get-computed-style-in-callback.html
+++ b/third_party/blink/web_tests/resize-observer/get-computed-style-in-callback.html
+<!doctype HTML>
+<script src="../resources/testharness.js"></script>
+<script src="../resources/testharnessreport.js"></script>
+
+<div id="sizeChangingDiv"></div>
+
+<script>
+test(() => {
+  document.body.offsetTop;
+  const resizeObserver = new ResizeObserver(() => assert_equals(getComputedStyle(document.body).height, "123px"));
+  resizeObserver.observe(sizeChangingDiv);
+  sizeChangingDiv.style.height = "123px";
+}, "getComputedStyle gets up-to-date style when called from within a ResizeObserver callback");
+</script>
+