Mark shadow root layout tree for rebuilding from style recalc.

third_party/WebKit/Source/core/dom/shadow/ShadowRoot.cpp

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Neither the name of Google Inc. nor the names of its
@@ skipping 124 matching lines @@
           markup, &host(), AllowScriptingContent, "innerHTML", exceptionState))
     replaceChildrenWithFragment(this, fragment, exceptionState);
 }
 
 void ShadowRoot::recalcStyle(StyleRecalcChange change) {
   // ShadowRoot doesn't support custom callbacks.
   DCHECK(!hasCustomStyleCallbacks());
 
   StyleSharingDepthScope sharingScope(*this);
 
-  if (getStyleChangeType() >= SubtreeStyleChange)
+  if (getStyleChangeType() >= SubtreeStyleChange) {
     change = Force;
+    if (needsAttach())
+      setNeedsReattachLayoutTree();
+  }
 
   // There's no style to update so just calling recalcStyle means we're updated.
   clearNeedsStyleRecalc();
 
   recalcDescendantStyles(change);
   clearChildNeedsStyleRecalc();
 }
 
 void ShadowRoot::rebuildLayoutTree() {
   // ShadowRoot doesn't support custom callbacks.
@@ skipping 186 matching lines @@
       ostream << "ShadowRootType::Open";
       break;
     case ShadowRootType::Closed:
       ostream << "ShadowRootType::Closed";
       break;
   }
   return ostream;
 }
 
 }  // namespace blink