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

Source/core/editing/DeleteSelectionCommand.cpp

 /*
  * Copyright (C) 2005 Apple Computer, Inc.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 324 matching lines @@
 
 void DeleteSelectionCommand::removeNode(PassRefPtrWillBeRawPtr<Node> node, ShouldAssumeContentIsAlwaysEditable shouldAssumeContentIsAlwaysEditable)
 {
     if (!node)
         return;
 
     if (m_startRoot != m_endRoot && !(node->isDescendantOf(m_startRoot.get()) && node->isDescendantOf(m_endRoot.get()))) {
         // If a node is not in both the start and end editable roots, remove it only if its inside an editable region.
         if (!node->parentNode()->hasEditableStyle()) {
             // Don't remove non-editable atomic nodes.
-            if (!node->firstChild())
+            if (!node->hasChildren())
                 return;
             // Search this non-editable region for editable regions to empty.
             RefPtrWillBeRawPtr<Node> child = node->firstChild();
             while (child) {
                 RefPtrWillBeRawPtr<Node> nextChild = child->nextSibling();
                 removeNode(child.get(), shouldAssumeContentIsAlwaysEditable);
                 // Bail if nextChild is no longer node's child.
                 if (nextChild && nextChild->parentNode() != node)
                     return;
                 child = nextChild;
@@ skipping 261 matching lines @@
 
     // m_downstreamEnd's block has been emptied out by deletion.  There is no content inside of it to
     // move, so just remove it.
     Element* endBlock = enclosingBlock(m_downstreamEnd.deprecatedNode());
     if (!endBlock || !endBlock->contains(startOfParagraphToMove.deepEquivalent().deprecatedNode()) || !startOfParagraphToMove.deepEquivalent().deprecatedNode()) {
         removeNode(enclosingBlock(m_downstreamEnd.deprecatedNode()));
         return;
     }
 
     // We need to merge into m_upstreamStart's block, but it's been emptied out and collapsed by deletion.
-    if (!mergeDestination.deepEquivalent().deprecatedNode() || (!mergeDestination.deepEquivalent().deprecatedNode()->isDescendantOf(enclosingBlock(m_upstreamStart.containerNode())) && (!mergeDestination.deepEquivalent().anchorNode()->firstChild() || !m_upstreamStart.containerNode()->firstChild())) || (m_startsAtEmptyLine && mergeDestination != startOfParagraphToMove)) {
+    if (!mergeDestination.deepEquivalent().deprecatedNode() || (!mergeDestination.deepEquivalent().deprecatedNode()->isDescendantOf(enclosingBlock(m_upstreamStart.containerNode())) && (!mergeDestination.deepEquivalent().anchorNode()->hasChildren() || !m_upstreamStart.containerNode()->hasChildren())) || (m_startsAtEmptyLine && mergeDestination != startOfParagraphToMove)) {
         insertNodeAt(createBreakElement(document()).get(), m_upstreamStart);
         mergeDestination = VisiblePosition(m_upstreamStart);
     }
 
     if (mergeDestination == startOfParagraphToMove)
         return;
 
     VisiblePosition endOfParagraphToMove = endOfParagraph(startOfParagraphToMove, CanSkipOverEditingBoundary);
 
     if (mergeDestination == endOfParagraphToMove)
@@ skipping 248 matching lines @@
     visitor->trace(m_deleteIntoBlockquoteStyle);
     visitor->trace(m_startRoot);
     visitor->trace(m_endRoot);
     visitor->trace(m_startTableRow);
     visitor->trace(m_endTableRow);
     visitor->trace(m_temporaryPlaceholder);
     CompositeEditCommand::trace(visitor);
 }
 
 } // namespace blink