offsetParent() fails to consider continuations when searching for the parent.

third_party/WebKit/Source/core/layout/LayoutObject.cpp

Index: third_party/WebKit/Source/core/layout/LayoutObject.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutObject.cpp b/third_party/WebKit/Source/core/layout/LayoutObject.cpp
index 766252d70d6bdd42ebb27ef0bbd76d8e34442683..5976f163e43cb9d98f1057fc1ca3505aad78d5d4 100644
--- a/third_party/WebKit/Source/core/layout/LayoutObject.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutObject.cpp
@@ -3217,8 +3217,20 @@ Element* LayoutObject::offsetParent(const Element* base) const {
 
     node = ancestor->node();
 
-    if (!node)
-      continue;
+    if (!node) {
+      if (!ancestor->virtualContinuation())
+        continue;
+
+      // This is an anonymous continuation; ie. our ancestor is really the split
+      // inline. Find it by spooling to the end of the continuation chain.
+
+      while (LayoutBoxModelObject* cont = ancestor->virtualContinuation())
+        ancestor = cont;
+
+      node = ancestor->node();
+
+      DCHECK(node);
+    }
 
     // TODO(kochi): If |base| or |node| is nested deep in shadow roots, this
     // loop may get expensive, as isUnclosedNodeOf() can take up to O(N+M) time