[LayoutNG] Fix for DCHECK(NeedsLayout) for fixed

All tests pass, and crashes no longer happen. I believe that code will not longer crash, but there might be futher instances of incorrect positioning. Fix #1 LayoutDescendantCandidates did not sweep newly discovered candidates. This was done manually once inside NGOutOfFlowLayoutPart::Run, and sweep was not performed for LayoutDescendantCandidates found in Legacy. Fix is to make LayoutDescendantCandidates perform sweep instead. Fix #2 fix #1 exposed a bug where duplicate fragments were generated for a single layout object. This happened when NG was generating fragments not inside ContainingBlock. Fix one instance of this inside NGOutOfFlowLayoutPart::IsContainingBlockForDescendant by making sure that OOF with inline containers are only positioned inside its ContainingBlock() Fix #3 NGOutOfFlowLayoutPart::LayoutDescendant offset adjustment. This one I am unsure about because I do not know exactly how split inlines generate anonymous boxes. if (container != container_builder_->GetLayoutObject() && container->Parent()->IsAnonymousBlock()) It extends the previus special case of css_container being anonymous. It seems that it should be somehow generalized to if "anything in ancestor chain to ContainerBlock() is anonymous?" Bug: 935805 Change-Id: I9f7ebbc7223f40fbbf6ba3739d9385bfd59e3641
web-platform-tests · Mar 12, 2019 · d9eb1dd · d9eb1dd
1 parent c7a85cb
commit d9eb1dd
Showing 1 changed file with 29 additions and 0 deletions.
diff --git a/css/css-position/position-absolute-crash-chrome-003.html b/css/css-position/position-absolute-crash-chrome-003.html
@@ -0,0 +1,29 @@
+<!DOCTYPE html>
+<title>CSS Position Absolute: Chrome chrash</title>
+<link rel="author" href="mailto:atotic@google.com">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<link rel="help" href="https://bugs.chromium.org/p/chromium/issues/detail?id=935805">
+<meta name="assert" content="Nested abs/fixed/flex do not crash">
+<style>
+  #flex {
+    display: flex;
+  }
+  .abs {
+    position: absolute;
+  }
+  #fixed {
+    position: fixed;
+  }
+</style>
+<div class="abs">
+  <div id="flex">
+    <div class="abs">
+      <div id="fixed"></div>
+    </div>
+  </div>
+</div>
+<script>
+test(() => {
+}, 'test passes if it does not crash');
+</script>