Add a flat_map container

base/containers/container_test_utils.h

Index: base/containers/container_test_utils.h
diff --git a/base/containers/container_test_utils.h b/base/containers/container_test_utils.h
new file mode 100644
index 0000000000000000000000000000000000000000..e36b9f731252a92510d481028299c1523a48b8c4
--- /dev/null
+++ b/base/containers/container_test_utils.h
@@ -0,0 +1,39 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.

[danakj, 2017/03/21 20:28:55]

Why is this not in base/test/ (and the test build target)?

+// 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_;
+  }
+
+  int data() const { return data_; }
+
+ private:
+  int data_;
+
+  DISALLOW_COPY_AND_ASSIGN(MoveOnlyInt);
+};
+
+}  // namespace base
+
+#endif  // BASE_CONTAINERS_CONTAINER_TEST_UTILS_H_