add maps and sets to zone containers

src/zone-containers.h

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_ZONE_CONTAINERS_H_
 #define V8_ZONE_CONTAINERS_H_
 
 #include <deque>
 #include <list>
+#include <map>
 #include <queue>
+#include <set>
 #include <stack>
 #include <vector>
 
 #include "src/zone-allocator.h"
 
 namespace v8 {
 namespace internal {
 
 // A wrapper subclass for std::vector to make it easy to construct one
 // that uses a zone allocator.
@@ skipping 55 matching lines @@
 // a zone allocator.
 template <typename T>
 class ZoneStack : public std::stack<T, ZoneDeque<T>> {
  public:
   // Constructs an empty stack.
   explicit ZoneStack(Zone* zone)
       : std::stack<T, ZoneDeque<T>>(ZoneDeque<T>(zone)) {}
 };
 
 
+// A wrapper subclass for std::set to make it easy to construct one that uses
+// a zone allocator.
+template <typename K, typename Compare = std::less<K>>
+class ZoneSet : public std::set<K, Compare, zone_allocator<K>> {
+ public:
+  // Constructs an empty set.
+  explicit ZoneSet(Zone* zone)
+      : std::set<K, Compare, zone_allocator<K>>(Compare(),
+                                                zone_allocator<K>(zone)) {}
+};
+
+
+// A wrapper subclass for std::map to make it easy to construct one that uses
+// a zone allocator.
+template <typename K, typename V, typename Compare = std::less<K>>
+class ZoneMap
+    : public std::map<K, V, Compare, zone_allocator<std::pair<K, V>>> {
+ public:
+  // Constructs an empty map.
+  explicit ZoneMap(Zone* zone)
+      : std::map<K, V, Compare, zone_allocator<std::pair<K, V>>>(
+            Compare(), zone_allocator<std::pair<K, V>>(zone)) {}
+};
+
+
 // Typedefs to shorten commonly used vectors.
 typedef ZoneVector<bool> BoolVector;
 typedef ZoneVector<int> IntVector;
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_ZONE_CONTAINERS_H_