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 43482a85797474481f9e2cccc4cb3732c79ab7c2..feeb105ece85d7a6a4cdd4501f3342ffda4c1701 100644
--- a/third_party/WebKit/Source/core/dom/Document.cpp
+++ b/third_party/WebKit/Source/core/dom/Document.cpp
@@ -1365,13 +1365,13 @@ Element* Document::scrollingElement() {
 // 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);

[ktyliu, 2017/01/13 02:04:05]

not related to your change, but "&node" should better be "node"?
(similarly below)

[Bugs Nash, 2017/01/13 02:08:40]

the set method is taking a Node* here (or more accurately a Member<Node> which
is a fancy pointer) so I believe &node is necessary

 }
 
-StyleReattachData Document::getStyleReattachData(Node& node) {
+StyleReattachData Document::getStyleReattachData(const Node& node) const {
   return m_styleReattachDataMap.get(&node);
 }