Added constness to the hashmap on Document.

third_party/WebKit/Source/core/dom/Document.cpp

Index: third_party/WebKit/Source/core/dom/Document.cpp
diff --git a/third_party/WebKit/Source/core/dom/Document.cpp b/third_party/WebKit/Source/core/dom/Document.cpp
index c6fc06017a7c105bef8143e3e0e3129be4534775..8dd0107b17f40243126d5ebf82ac2ec8a0e5a7b0 100644
--- a/third_party/WebKit/Source/core/dom/Document.cpp
+++ b/third_party/WebKit/Source/core/dom/Document.cpp
@@ -1369,13 +1369,13 @@ Element* Document::scrollingElementNoLayout() {
 // We use HashMap::set over HashMap::add here as we want to
 // replace the ComputedStyle but not the Node if the Node is
 // already present.
-void Document::addStyleReattachData(Node& node,
+void Document::addStyleReattachData(const Node& node,
                                     StyleReattachData& styleReattachData) {
   DCHECK(node.isElementNode() || node.isTextNode());
   m_styleReattachDataMap.set(&node, styleReattachData);
 }
 
-StyleReattachData Document::getStyleReattachData(Node& node) {
+StyleReattachData Document::getStyleReattachData(const Node& node) const {
   return m_styleReattachDataMap.get(&node);
 }