Refactoring: HashMap: provide a pointer match function, so users don't need to.

src/hashmap.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 80 matching lines @@
   //
   // for (Entry* p = map.Start(); p != NULL; p = map.Next(p)) {
   //   ...
   // }
   //
   // If entries are inserted during iteration, the effect of
   // calling Next() is undefined.
   Entry* Start() const;
   Entry* Next(Entry* p) const;
 
+  // Some match functions defined for convenience.
+  static bool PointersMatch(void* key1, void* key2) {
+    return key1 == key2;
+  }
+
  private:
   MatchFun match_;
   Entry* map_;
   uint32_t capacity_;
   uint32_t occupancy_;
 
   Entry* map_end() const { return map_ + capacity_; }
   Entry* Probe(void* key, uint32_t hash);
   void Initialize(uint32_t capacity, AllocationPolicy allocator);
   void Resize(AllocationPolicy allocator);
@@ skipping 244 matching lines @@
   Iterator end() const { return Iterator(this, NULL); }
   Iterator find(Key* key, bool insert = false,
                 AllocationPolicy allocator = AllocationPolicy()) {
     return Iterator(this, this->Lookup(key, key->Hash(), insert, allocator));
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_HASHMAP_H_