WTF: Implement move of Deques.

third_party/WebKit/Source/wtf/DequeTest.cpp

 /*
  * Copyright (C) 2011 Apple 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 548 matching lines @@
     EXPECT_EQ(0u, deque.size());
 
     deque.append(Pointer(new int(42)));
     deque[0] = Pointer(new int(24));
     ASSERT_EQ(1u, deque.size());
     EXPECT_EQ(24, *deque[0]);
 
     deque.clear();
 }
 
+class CountCopy final {
+public:
+    explicit CountCopy(int* counter = nullptr) : m_counter(counter) { }
+    CountCopy(const CountCopy& other)
+        : m_counter(other.m_counter)
+    {
+        if (m_counter)
+            ++*m_counter;
+    }
+    CountCopy& operator=(const CountCopy& other)
+    {
+        m_counter = other.m_counter;
+        if (m_counter)
+            ++*m_counter;
+        return *this;
+    }
+
+private:
+    int* m_counter;
+};
+
+TEST(DequeTest, MoveShouldNotMakeCopy)
+{
+    // Because data in inline buffer may be swapped or moved individually, we force the creation of out-of-line buffer
+    // so we can make sure there's no element-wise copy/move.
+    Deque<CountCopy, 1> deque;
+    int counter = 0;
+    deque.append(CountCopy(&counter));
+    deque.append(CountCopy(&counter));
+
+    Deque<CountCopy, 1> other(deque);
+    counter = 0;
+    deque = std::move(other); // Move assignment.
+    EXPECT_EQ(0, counter);
+
+    counter = 0;
+    Deque<CountCopy, 1> yetAnother(std::move(deque)); // Move construction.
+    EXPECT_EQ(0, counter);
+}
+
 } // anonymous namespace
 
 } // namespace WTF