DL: Ensure to force scoped updates to the local frame root.

This patch ensures that when forcing a layout we force it all the way
up to the local frame root, since the dimensions of the frame may have
an effect on the properties of the queried element.

R=chrishtr@chromium.org, rakina@chromium.org, szager@chromium.org

Change-Id: I9cfdb38560e9cd75a45d87d9749c92cac0016a61
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1695660Reviewed-by: Stefan Zager <szager@chromium.org>
Commit-Queue: vmpstr <vmpstr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#676108}

third_party/blink/renderer/core/display_lock/display_lock_utilities.cc

@@ -15,6 +15,19 @@
 #include "third_party/blink/renderer/core/layout/layout_view.h"
 
 namespace blink {
+namespace {
+
+// Returns the frame owner node for the frame that contains the given child, if
+// one exists. Returns nullptr otherwise.
+const Node* GetFrameOwnerNode(const Node* child) {
+  if (!child || !child->GetDocument().GetFrame() ||
+      !child->GetDocument().GetFrame()->OwnerLayoutObject()) {
+    return nullptr;
+  }
+  return child->GetDocument().GetFrame()->OwnerLayoutObject()->GetNode();
+}
+
+}  // namespace
 
 bool DisplayLockUtilities::ActivateFindInPageMatchRangeIfNeeded(
     const EphemeralRangeInFlatTree& range) {
@@ -64,22 +77,28 @@ DisplayLockUtilities::ActivatableLockedInclusiveAncestors(Element& element) {
 }
 
 DisplayLockUtilities::ScopedChainForcedUpdate::ScopedChainForcedUpdate(
-    const Node* node) {
-  if (!RuntimeEnabledFeatures::DisplayLockingEnabled() ||
-      node->GetDocument().LockedDisplayLockCount() == 0) {
+    const Node* node,
+    bool include_self) {
+  if (!RuntimeEnabledFeatures::DisplayLockingEnabled())
+    return;
+
+  CreateParentFrameScopeIfNeeded(node);
+
+  if (node->GetDocument().LockedDisplayLockCount() == 0)
     return;
-  }
   const_cast<Node*>(node)->UpdateDistributionForFlatTreeTraversal();
 
   // Get the right ancestor view. Only use inclusive ancestors if the node
   // itself is locked and it prevents self layout. If self layout is not
   // prevented, we don't need to force the subtree layout, so use exclusive
   // ancestors in that case.
-  auto ancestor_view = [node] {
+  auto ancestor_view = [node, include_self] {
     if (auto* element = DynamicTo<Element>(node)) {
       auto* context = element->GetDisplayLockContext();
-      if (context && !context->ShouldLayout(DisplayLockContext::kSelf))
+      if (context &&
+          (include_self || !context->ShouldLayout(DisplayLockContext::kSelf))) {
         return FlatTreeTraversal::InclusiveAncestorsOf(*node);
+      }
     }
     return FlatTreeTraversal::AncestorsOf(*node);
   }();
@@ -98,6 +117,15 @@ DisplayLockUtilities::ScopedChainForcedUpdate::ScopedChainForcedUpdate(
   }
 }
 
+void DisplayLockUtilities::ScopedChainForcedUpdate::
+    CreateParentFrameScopeIfNeeded(const Node* node) {
+  auto* owner_node = GetFrameOwnerNode(node);
+  if (owner_node) {
+    parent_frame_scope_ =
+        std::make_unique<ScopedChainForcedUpdate>(owner_node, true);
+  }
+}
+
 const Element* DisplayLockUtilities::NearestLockedInclusiveAncestor(
     const Node& node) {
   auto* element = DynamicTo<Element>(node);
@@ -187,26 +215,18 @@ bool DisplayLockUtilities::IsInLockedSubtreeCrossingFrames(
       return true;
   }
 
-  auto get_frame_owner_node = [](const Node* child) -> const Node* {
-    if (!child || !child->GetDocument().GetFrame() ||
-        !child->GetDocument().GetFrame()->OwnerLayoutObject()) {
-      return nullptr;
-    }
-    return child->GetDocument().GetFrame()->OwnerLayoutObject()->GetNode();
-  };
-
   // Since we handled the self-check above, we need to do inclusive checks
   // starting from the parent.
   node = FlatTreeTraversal::Parent(*node);
   // If we don't have a flat-tree parent, get the |source_node|'s owner node
   // instead.
   if (!node)
-    node = get_frame_owner_node(&source_node);
+    node = GetFrameOwnerNode(&source_node);
 
   while (node) {
     if (NearestLockedInclusiveAncestor(*node))
       return true;
-    node = get_frame_owner_node(node);
+    node = GetFrameOwnerNode(node);
   }
   return false;
 }

third_party/blink/renderer/core/display_lock/display_lock_utilities.h

@@ -18,17 +18,20 @@ class CORE_EXPORT DisplayLockUtilities {
 
  public:
   // This class forces updates on display locks from the given node up the
-  // ancestor chain until the root.
+  // ancestor chain until the local frame root.
   class ScopedChainForcedUpdate {
-    STACK_ALLOCATED();
     DISALLOW_COPY_AND_ASSIGN(ScopedChainForcedUpdate);
 
    public:
-    explicit ScopedChainForcedUpdate(const Node* node);
+    explicit ScopedChainForcedUpdate(const Node* node,
+                                     bool include_self = false);
     ~ScopedChainForcedUpdate() = default;
 
+    void CreateParentFrameScopeIfNeeded(const Node* node);
+
    private:
     Vector<DisplayLockContext::ScopedForcedUpdate> scoped_update_forced_list_;
+    std::unique_ptr<ScopedChainForcedUpdate> parent_frame_scope_;
   };
   // Activates all the nodes within a find-in-page match |range|.
   // Returns true if at least one node gets activated.

third_party/blink/web_tests/wpt_internal/display-lock/lock-after-append/get-bounding-client-rect-block-layout-in-iframe.html

+<!doctype HTML>
+<html>
+<meta charset="utf8">
+<title>Display Locking: getBoundingClientRect on block layout</title>
+<link rel="author" title="Rakina Zata Amni" href="mailto:rakina@chromium.org">
+<link rel="help" href="https://github.com/WICG/display-locking">
+
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<style>
+#container {
+  contain: style layout;
+  width: 123px;
+  height: 234px;
+}
+#frame {
+  padding: 0;
+  margin: 0;
+  width: 500px;
+  height: 500px;
+}
+</style>
+<body>
+<div id="container">
+  <iframe id="frame" frameborder=0 srcdoc='
+    <style>
+      body {
+        padding: 0;
+        margin: 0;
+      }
+      #target {
+        background: lightgreen;
+        width: 50%;
+        height: 50px;
+      }
+    </style>
+    <div id="target"></div>
+  '></iframe>
+</div>
+
+<script>
+let load_promise = new Promise((resolve) => {
+  window.onload = resolve;
+});
+
+async_test(async(t) => {
+  await load_promise;
+
+  const container = document.getElementById("container");
+  await container.displayLock.acquire({ timeout: Infinity });
+
+  const frame = document.getElementById("frame");
+  frame.style.width = "224px";
+  frame.style.height = "248px";
+
+  const target = frame.contentDocument.getElementById("target");
+  t.step(() => assert_true(!!target, "sanity check that target exists"));
+  let rect = target.getBoundingClientRect();
+  t.step(() => assert_equals(rect.width, 112, "target uses update frame size for width"));
+  t.step(() => assert_equals(rect.height, 50, "target uses set size for height"));
+
+  t.done();
+}, "getBoundingClientRect in iframe");
+
+</script>
+</body>
+</html>