Get rid of inefficient uses of childNodeCount()

Source/core/editing/markup.cpp

Index: Source/core/editing/markup.cpp
diff --git a/Source/core/editing/markup.cpp b/Source/core/editing/markup.cpp
index ce7484641725632a31205dbabf8cb6e86c49a584..b2b6522670ac9cfcf47fb4acd05db38a83f5a83d 100644
--- a/Source/core/editing/markup.cpp
+++ b/Source/core/editing/markup.cpp
@@ -369,7 +369,7 @@ Node* StyledMarkupAccumulator::traverseNodesForSerialization(Node* startNode, No
                 appendStartTag(*n);
 
             // If node has no children, close the tag now.
-            if (!n->childNodeCount()) {
+            if (!n->hasChildNodes()) {
                 if (shouldEmit)
                     appendEndTag(*n);
                 lastClosed = n;
@@ -782,15 +782,20 @@ static void fillContainerFromString(ContainerNode* paragraph, const String& stri
     }
 }
 
-bool isPlainTextMarkup(Node *node)
+bool isPlainTextMarkup(Node* node)
 {
-    if (!node->isElementNode() || !node->hasTagName(divTag) || toElement(node)->hasAttributes())
+    if (!node->isElementNode())
         return false;
 
-    if (node->childNodeCount() == 1 && (node->firstChild()->isTextNode() || (node->firstChild()->firstChild())))
+    Element* element = toElement(node);
+    if (!element->hasTagName(divTag) || !element->hasAttributes())
+        return false;
+
+    if (element->hasOneChild() && (element->firstChild()->isTextNode() || (element->firstChild()->firstChild())))
         return true;
 
-    return (node->childNodeCount() == 2 && isTabSpanTextNode(node->firstChild()->firstChild()) && node->firstChild()->nextSibling()->isTextNode());
+    bool elementHasTwoChildren = (element->firstChild() && element->firstChild()->nextSibling() && !element->firstChild()->nextSibling()->nextSibling());

[eseidel, 2014/02/19 05:39:54]

I wonder if a generic hasChildCount(unsigned) is useful.

[Inactive, 2014/02/19 14:28:15]

This is likely the only place where we would need it but why not. At least,
people would be less prone to using childNodeCount() for such use cases. I'll
look into this now.

+    return (elementHasTwoChildren && isTabSpanTextNode(element->firstChild()->firstChild()) && element->firstChild()->nextSibling()->isTextNode());
 }
 
 static bool shouldPreserveNewline(const Range& range)