Added constness to the hashmap on Document.

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

Index: third_party/WebKit/Source/core/dom/Document.h
diff --git a/third_party/WebKit/Source/core/dom/Document.h b/third_party/WebKit/Source/core/dom/Document.h
index 47df5cc4ba95ff8578e3cfaab36c464463590075..39489d86bb1bc0e17b05d98a0f2ab8ae0c3d277b 100644
--- a/third_party/WebKit/Source/core/dom/Document.h
+++ b/third_party/WebKit/Source/core/dom/Document.h
@@ -345,8 +345,8 @@ class CORE_EXPORT Document : public ContainerNode,
   Range* caretRangeFromPoint(int x, int y);
   Element* scrollingElement();
 
-  void addStyleReattachData(Node&, StyleReattachData&);
-  StyleReattachData getStyleReattachData(Node&);
+  void addStyleReattachData(const Node&, StyleReattachData&);
+  StyleReattachData getStyleReattachData(const Node&) const;
 
   String readyState() const;
 
@@ -1446,7 +1446,7 @@ class CORE_EXPORT Document : public ContainerNode,
   // This HashMap is used to stash information (ComputedStyle, nextTextSibling)
   // generated in the Style Resolution phase that is required in the
   // Layout Tree construction phase.
-  HeapHashMap<Member<Node>, StyleReattachData> m_styleReattachDataMap;
+  HeapHashMap<Member<const Node>, StyleReattachData> m_styleReattachDataMap;
 
   bool m_wellFormed;