Reverse style resolution to avoid N^2 walk when building the render tree

Source/core/dom/Node.cpp

Index: Source/core/dom/Node.cpp
diff --git a/Source/core/dom/Node.cpp b/Source/core/dom/Node.cpp
index 2c8d620ea48559f00c226405bcb8c5dade6e15c4..adc0f91e293ac28d33c3451023e2a865f72026b7 100644
--- a/Source/core/dom/Node.cpp
+++ b/Source/core/dom/Node.cpp
@@ -1030,6 +1030,20 @@ void Node::detach(const AttachContext& context)
 #endif
 }
 
+void Node::reattachWhitespaceSiblings() const
+{
+    for (Node* sibling = nextSibling(); sibling; sibling = sibling->nextSibling()) {
+        if (sibling->renderer())
+            return;
+        if (sibling->isTextNode()) {
+            if (toText(sibling)->containsOnlyWhitespace())
+                sibling->reattach();
+            else
+                return;
+        }
+    }
+}
+
 // FIXME: This code is used by editing.  Seems like it could move over there and not pollute Node.
 Node *Node::previousNodeConsideringAtomicNodes() const
 {