Revert of Avoid argument copying in WTF hash-based containers

Source/wtf/HashMapTest.cpp

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 285 matching lines @@
 
 TEST(HashMapTest, ValueTypeDestructed)
 {
     InstanceCounter::counter = 0;
     HashMap<int, InstanceCounter> map;
     map.set(1, InstanceCounter());
     map.clear();
     EXPECT_EQ(0, InstanceCounter::counter);
 }
 
-class CopyCounter {
-public:
-    CopyCounter() = default;
-    explicit CopyCounter(int data) : m_data(data) { }
-
-    CopyCounter(const CopyCounter& copy) : m_data(copy.m_data) { ++s_counter; }
-
-    int data() const { return m_data; }
-
-    bool isHashTableDeletedValue() const { return m_data == HashTableDeletedValue; }
-
-    static int s_counter;
-private:
-    int m_data;
-};
-
-int CopyCounter::s_counter = 0;
-
-struct CopyCounterHash {
-    static unsigned hash(const CopyCounter& key)
-    {
-        return IntHash<unsigned>::hash(key.data());
-    }
-
-    static bool equal(const CopyCounter& a, const CopyCounter& b)
-    {
-        return a.data() == b.data();
-    }
-
-    static const bool safeToCompareToEmptyOrDeleted = true;
-};
-
-struct CopyCounterHashTraits: SimpleClassHashTraits<CopyCounter> {
-#if COMPILER(MSVC)
-    // Need this in order to enable RVO on VS2013 (the default traits
-    // implementation would produce an unneeded copy).
-    static CopyCounter emptyValue()
-    {
-        CopyCounter empty;
-        return empty;
-    }
-#endif
-    static const bool hasIsEmptyValueFunction = true;
-    static bool isEmptyValue(const CopyCounter& counter) { return !counter.data(); }
-};
-
-TEST(HashMapTest, LookupNoKeyCopies)
-{
-    HashMap<CopyCounter, int, CopyCounterHash, CopyCounterHashTraits> map;
-
-    map.contains(CopyCounter(1));
-    auto it = map.find(CopyCounter(1));
-    ALLOW_UNUSED_LOCAL(it);
-    EXPECT_EQ(0, CopyCounter::s_counter);
-}
-
 } // anonymous namespace
 
 } // namespace WTF