Added constness to the hashmap on Document.

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All
  * rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved.
  * (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
@@ skipping 1347 matching lines @@
 
     return documentElement();
   }
 
   return body();
 }
 
 // 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);
 }
 
 /*
  * Performs three operations:
  *  1. Convert control characters to spaces
  *  2. Trim leading and trailing spaces
  *  3. Collapse internal whitespace.
  */
 template <typename CharacterType>
@@ skipping 5198 matching lines @@
 }
 
 void showLiveDocumentInstances() {
   WeakDocumentSet& set = liveDocumentSet();
   fprintf(stderr, "There are %u documents currently alive:\n", set.size());
   for (Document* document : set)
     fprintf(stderr, "- Document %p URL: %s\n", document,
             document->url().getString().utf8().data());
 }
 #endif