Call Element::rebuildLayoutTree from Document::updateStyle directly

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

Index: third_party/WebKit/Source/core/dom/Document.cpp
diff --git a/third_party/WebKit/Source/core/dom/Document.cpp b/third_party/WebKit/Source/core/dom/Document.cpp
index f5972c64070085e883e96563363867652c7fe6a3..b2f5f8b54f9370c91ab21a100e208a735be22c11 100644
--- a/third_party/WebKit/Source/core/dom/Document.cpp
+++ b/third_party/WebKit/Source/core/dom/Document.cpp
@@ -1368,13 +1368,13 @@ Element* Document::scrollingElement() {
 // We use HashMap::set over HashMap::add here as we want to
 // replace the ComputedStyle but not the Element if the Element is
 // already present.
-void Document::addStyleReattachData(Element& element,
+void Document::addStyleReattachData(Node& node,
                                     StyleReattachData& styleReattachData) {
-  m_styleReattachDataMap.set(&element, styleReattachData);
+  m_styleReattachDataMap.set(&node, styleReattachData);
 }
 
-StyleReattachData Document::getStyleReattachData(Element& element) {
-  return m_styleReattachDataMap.get(&element);
+StyleReattachData Document::getStyleReattachData(Node& node) {
+  return m_styleReattachDataMap.get(&node);
 }
 
 /*
@@ -1800,7 +1800,7 @@ void Document::inheritHtmlAndBodyElementStyles(StyleRecalcChange change) {
   // for viewport styles, but we assume root font size changes are rare and just
   // invalidate the cache for now.
   if (styleEngine().usesRemUnits() &&
-      (documentElement()->needsAttach() ||
+      (documentElement()->needsReattachLayoutTree() ||
        !documentElement()->computedStyle() ||
        documentElement()->computedStyle()->fontSize() !=
            documentElementStyle->fontSize())) {
@@ -2051,6 +2051,11 @@ void Document::updateStyle() {
     inheritHtmlAndBodyElementStyles(change);
     if (documentElement->shouldCallRecalcStyle(change))
       documentElement->recalcStyle(change);
+    DCHECK(!documentElement->needsStyleRecalc());
+    DCHECK(!documentElement->childNeedsStyleRecalc());
+    if (documentElement->needsReattachLayoutTree() ||
+        documentElement->childNeedsReattachLayoutTree())
+      documentElement->rebuildLayoutTree();
   }
 
   view()->recalcOverflowAfterStyleChange();
@@ -2368,9 +2373,11 @@ void Document::initialize() {
   m_layoutView->setStyle(StyleResolver::styleForDocument(*this));
   m_layoutView->compositor()->setNeedsCompositingUpdate(
       CompositingUpdateAfterCompositingInputChange);
-
+  setNeedsReattachLayoutTree();

[nainar, 2016/11/29 06:13:39]

This is as ContainerNode::attachLayoutTree() asserts that this flag is set. 

   ContainerNode::attachLayoutTree();
 
+  DCHECK(!needsReattachLayoutTree());
+
   // The TextAutosizer can't update layout view info while the Document is
   // detached, so update now in case anything changed.
   if (TextAutosizer* autosizer = textAutosizer())