Add a remove method to the hash map

src/hashmap.h

 // Copyright 2008 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 57 matching lines @@
     uint32_t hash;  // the full hash value for key
   };
 
   // If an entry with matching key is found, Lookup()
   // returns that entry. If no matching entry is found,
   // but insert is set, a new entry is inserted with
   // corresponding key, key hash, and NULL value.
   // Otherwise, NULL is returned.
   Entry* Lookup(void* key, uint32_t hash, bool insert);
 
+  // Removes the entry with matching key.
+  void Remove(void* key, uint32_t hash);
+
   // Empties the hash map (occupancy() == 0).
   void Clear();
 
   // The number of (non-empty) entries in the table.
   uint32_t occupancy() const  { return occupancy_; }
 
   // The capacity of the table. The implementation
   // makes sure that occupancy is at most 80% of
   // the table capacity.
   uint32_t capacity() const  { return capacity_; }
@@ skipping 19 matching lines @@
   Entry* map_end() const  { return map_ + capacity_; }
   Entry* Probe(void* key, uint32_t hash);
   void Initialize(uint32_t capacity);
   void Resize();
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_HASHMAP_H_