Removing (dest != prev) check from LastUnique algorithm.

base/containers/container_test_utils.h

 // Copyright 2017 The Chromium 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 BASE_CONTAINERS_CONTAINER_TEST_UTILS_H_
 #define BASE_CONTAINERS_CONTAINER_TEST_UTILS_H_
 
 // This file contains some helper classes for testing conainer behavior.
 
 #include "base/macros.h"
 
 namespace base {
 
 // A move-only class that holds an integer.
 class MoveOnlyInt {
  public:
   explicit MoveOnlyInt(int data = 1) : data_(data) {}
   MoveOnlyInt(MoveOnlyInt&& other) : data_(other.data_) { other.data_ = 0; }
   MoveOnlyInt& operator=(MoveOnlyInt&& other) {
     data_ = other.data_;
     other.data_ = 0;
     return *this;
   }
 
+  friend bool operator==(const MoveOnlyInt& lhs, const MoveOnlyInt& rhs) {
+    return lhs.data_ == rhs.data_;
+  }
+
+  friend bool operator!=(const MoveOnlyInt& lhs, const MoveOnlyInt& rhs) {
+    return !operator==(lhs, rhs);
+  }
+
   friend bool operator<(const MoveOnlyInt& lhs, const MoveOnlyInt& rhs) {
     return lhs.data_ < rhs.data_;
   }
 
+  friend bool operator>(const MoveOnlyInt& lhs, const MoveOnlyInt& rhs) {
+    return rhs < lhs;
+  }
+
+  friend bool operator<=(const MoveOnlyInt& lhs, const MoveOnlyInt& rhs) {
+    return !(rhs < lhs);
+  }
+
+  friend bool operator>=(const MoveOnlyInt& lhs, const MoveOnlyInt& rhs) {
+    return !(lhs < rhs);
+  }
+
   int data() const { return data_; }
 
  private:
   int data_;
 
   DISALLOW_COPY_AND_ASSIGN(MoveOnlyInt);
 };
 
 }  // namespace base
 
 #endif  // BASE_CONTAINERS_CONTAINER_TEST_UTILS_H_