Don't create layout objects for children of display-none iframes.

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

Index: third_party/WebKit/Source/core/dom/Element.cpp
diff --git a/third_party/WebKit/Source/core/dom/Element.cpp b/third_party/WebKit/Source/core/dom/Element.cpp
index 7c286936357b055b17ba342c2581c8daf2be69cc..5c2895c103340ff6dd0ccf1f44d797c47896cd2d 100644
--- a/third_party/WebKit/Source/core/dom/Element.cpp
+++ b/third_party/WebKit/Source/core/dom/Element.cpp
@@ -1944,6 +1944,11 @@ StyleRecalcChange Element::recalcOwnStyle(StyleRecalcChange change,
     INCREMENT_STYLE_STATS_COUNTER(document().styleEngine(), stylesChanged, 1);
   }
 
+  // TODO: This is the wrong approach, but gets the job done. Find a more
+  // appropriate way of doing the same thing.
+  if (forceReattachDuringStyleRecalc())

[esprehn, 2016/12/10 02:20:55]

Remove this, we don't want an extra branch for every element in the entire
document. Just doing lazyReattach on the documentElement is enough.

+    localChange = Reattach;
+
   if (localChange == Reattach) {
     StyleReattachData styleReattachData;
     styleReattachData.computedStyle = std::move(newStyle);