Add intentional optimization comment in Node::setTextContent

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 8af4165eb24a4b736848148c34141be39e915632..d363f32a42d7cec22e08e99af6db878199dda050 100644
--- a/Source/core/dom/Node.cpp
+++ b/Source/core/dom/Node.cpp
@@ -1515,9 +1515,13 @@ void Node::setTextContent(const String& text)
         case DOCUMENT_FRAGMENT_NODE: {
             // FIXME: Merge this logic into replaceChildrenWithText.
             RefPtrWillBeRawPtr<ContainerNode> container = toContainerNode(this);
+
+            // Note: This is an intentional optimization.
+            // See crbug.com/352836 also.
             // No need to do anything if the text is identical.
             if (container->hasOneTextChild() && toText(container->firstChild())->data() == text)
                 return;
+
             ChildListMutationScope mutation(*this);
             container->removeChildren();
             // Note: This API will not insert empty text nodes: