Use ContainerNode::hasChildren() instead of firstChild() in conditionals

Source/core/editing/SimplifyMarkupCommand.cpp

Index: Source/core/editing/SimplifyMarkupCommand.cpp
diff --git a/Source/core/editing/SimplifyMarkupCommand.cpp b/Source/core/editing/SimplifyMarkupCommand.cpp
index 976ef726d91fae64849a6f43eaea46800fa3b2f7..8379318b300b6c9ac6422cb22f90b4fdb48db01d 100644
--- a/Source/core/editing/SimplifyMarkupCommand.cpp
+++ b/Source/core/editing/SimplifyMarkupCommand.cpp
@@ -49,7 +49,7 @@ void SimplifyMarkupCommand::doApply()
     // from a verbose fragment.
     // We look at inline elements as well as non top level divs that don't have attributes.
     for (Node* node = m_firstNode.get(); node && node != m_nodeAfterLast; node = NodeTraversal::next(*node)) {
-        if (node->firstChild() || (node->isTextNode() && node->nextSibling()))
+        if (node->hasChildren() || (node->isTextNode() && node->nextSibling()))
             continue;
 
         Node* startingNode = node->parentNode();