Fix memory leak in RootIndexMap.

R=mvstanton@chromium.org

Review URL: https://codereview.chromium.org/671153002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24831 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/serialize.h

@@ -169,6 +169,8 @@ class RootIndexMap : public AddressMapBase {
  public:
   explicit RootIndexMap(Isolate* isolate);
 
+  ~RootIndexMap() { delete map_; }
+
   static const int kInvalidRootIndex = -1;
   int Lookup(HeapObject* obj) {
     HashMap::Entry* entry = LookupEntry(map_, obj, false);