Move Node/ContainerNode's traverseToChildAt() to NodeTraversal

Source/core/editing/TextIterator.cpp

Index: Source/core/editing/TextIterator.cpp
diff --git a/Source/core/editing/TextIterator.cpp b/Source/core/editing/TextIterator.cpp
index de20c1cc343fe3c6c7266fa80872eb5f29b3258f..974ae2b6fbea5a358ace88d83c4dd688c4ba22fb 100644
--- a/Source/core/editing/TextIterator.cpp
+++ b/Source/core/editing/TextIterator.cpp
@@ -176,7 +176,7 @@ static Node* nextInPreOrderCrossingShadowBoundaries(Node* rangeEndContainer, int
     if (!rangeEndContainer)
         return 0;
     if (rangeEndOffset >= 0 && !rangeEndContainer->offsetInCharacters()) {
-        if (Node* next = rangeEndContainer->traverseToChildAt(rangeEndOffset))
+        if (Node* next = NodeTraversal::childAt(*rangeEndContainer, rangeEndOffset))
             return next;
     }
     for (Node* node = rangeEndContainer; node; node = node->parentOrShadowHostNode()) {
@@ -332,7 +332,7 @@ void TextIterator::initialize(const Position& start, const Position& end)
     // Set up the current node for processing.
     if (startContainer->offsetInCharacters())
         m_node = startContainer;
-    else if (Node* child = startContainer->traverseToChildAt(startOffset))
+    else if (Node* child = NodeTraversal::childAt(*startContainer, startOffset))
         m_node = child;
     else if (!startOffset)
         m_node = startContainer;
@@ -1214,7 +1214,7 @@ Node* TextIterator::node() const
     if (node->offsetInCharacters())
         return node;
 
-    return node->traverseToChildAt(textRange->startOffset());
+    return NodeTraversal::childAt(*node, textRange->startOffset());
 }
 
 // --------
@@ -1255,17 +1255,17 @@ SimplifiedBackwardsTextIterator::SimplifiedBackwardsTextIterator(const Range* r,
     int endOffset = r->endOffset();
 
     if (!startNode->offsetInCharacters() && startOffset >= 0) {
-        // traverseToChildAt() will return 0 if the offset is out of range. We rely on this behavior
+        // NodeTraversal::childAt() will return 0 if the offset is out of range. We rely on this behavior
         // instead of calling countChildren() to avoid traversing the children twice.
-        if (Node* childAtOffset = startNode->traverseToChildAt(startOffset)) {
+        if (Node* childAtOffset = NodeTraversal::childAt(*startNode, startOffset)) {
             startNode = childAtOffset;
             startOffset = 0;
         }
     }
     if (!endNode->offsetInCharacters() && endOffset > 0) {
-        // traverseToChildAt() will return 0 if the offset is out of range. We rely on this behavior
+        // NodeTraversal::childAt() will return 0 if the offset is out of range. We rely on this behavior
         // instead of calling countChildren() to avoid traversing the children twice.
-        if (Node* childAtOffset = endNode->traverseToChildAt(endOffset - 1)) {
+        if (Node* childAtOffset = NodeTraversal::childAt(*endNode, endOffset - 1)) {
             endNode = childAtOffset;
             endOffset = lastOffsetInNode(endNode);
         }