Implement the inert attribute

third_party/WebKit/Source/core/dom/Node.cpp

Index: third_party/WebKit/Source/core/dom/Node.cpp
diff --git a/third_party/WebKit/Source/core/dom/Node.cpp b/third_party/WebKit/Source/core/dom/Node.cpp
index 7d8415f0b1a934c007004df3e9fc46dcb54354ce..be953cac6736f98a354fd1e0d7d34f814856b18d 100644
--- a/third_party/WebKit/Source/core/dom/Node.cpp
+++ b/third_party/WebKit/Source/core/dom/Node.cpp
@@ -828,11 +828,27 @@ bool Node::ShouldHaveFocusAppearance() const {
 }
 
 bool Node::IsInert() const {
+  if (!CanParticipateInFlatTree())
+    return true;
+
+  DCHECK(!ChildNeedsDistributionRecalc());
+
   const HTMLDialogElement* dialog = GetDocument().ActiveModalDialog();
   if (dialog && this != GetDocument() &&
-      (!CanParticipateInFlatTree() ||
-       !FlatTreeTraversal::ContainsIncludingPseudoElement(*dialog, *this)))
+      !FlatTreeTraversal::ContainsIncludingPseudoElement(*dialog, *this)) {
     return true;
+  }
+
+  if (RuntimeEnabledFeatures::inertAttributeEnabled()) {
+    const Element* element = this->IsElementNode()
+                                 ? ToElement(this)
+                                 : FlatTreeTraversal::ParentElement(*this);
+    while (element) {
+      if (element->hasAttribute(HTMLNames::inertAttr))
+        return true;
+      element = FlatTreeTraversal::ParentElement(*element);
+    }
+  }
   return GetDocument().LocalOwner() && GetDocument().LocalOwner()->IsInert();

[dmazzoni, 2017/05/08 06:06:09]

I just realized this only walks local frames, so it won't work with
out-of-process iframes.

I think there's going to have to be a frame flag indicating whether
or not an entire frame / document is inert.

 }