cc: Add RandomAccessListContainer, which has more restricted API.

cc/base/random_access_list_container_unittest.cc

+// Copyright 2015 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.
+
+#include "cc/base/random_access_list_container.h"
+
+#include <algorithm>
+#include <vector>
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace cc {
+namespace {
+
+class Base {
+ public:
+  virtual ~Base() {}
+  int get_value() const { return value_; }
+
+ protected:
+  explicit Base(int value) : value_(value) {}
+
+  int value_;
+};
+
+const int kMagicNumberOne = 1;
+const int kMagicNumberTwo = 2;
+const int kMagicNumberThree = 3;
+
+class Derived1 : public Base {
+ public:
+  Derived1() : Base(kMagicNumberOne) {}
+};
+
+class Derived2 : public Base {
+ public:
+  Derived2() : Base(kMagicNumberTwo) {}
+};
+
+class Derived3 : public Base {
+ public:
+  Derived3() : Base(kMagicNumberThree) {}
+};
+
+size_t LargestDerivedElementSize() {
+  static_assert(sizeof(Derived1) >= sizeof(Derived2),
+                "Derived2 is larger than Derived1");
+  static_assert(sizeof(Derived1) >= sizeof(Derived3),
+                "Derived3 is larger than Derived1");
+  return sizeof(Derived1);
+}
+
+TEST(RandomAccessListContainerTest, RandomAccess) {
+  RandomAccessListContainer<Base> list(LargestDerivedElementSize(), 1);
+
+  list.AllocateAndConstruct<Derived1>();
+  list.AllocateAndConstruct<Derived2>();
+  list.AllocateAndConstruct<Derived3>();
+  list.AllocateAndConstruct<Derived1>();
+  list.AllocateAndConstruct<Derived2>();
+  list.AllocateAndConstruct<Derived3>();
+
+  EXPECT_EQ(kMagicNumberOne, list[0]->get_value());
+  EXPECT_EQ(kMagicNumberTwo, list[1]->get_value());
+  EXPECT_EQ(kMagicNumberThree, list[2]->get_value());
+  EXPECT_EQ(kMagicNumberOne, list[3]->get_value());
+  EXPECT_EQ(kMagicNumberTwo, list[4]->get_value());
+  EXPECT_EQ(kMagicNumberThree, list[5]->get_value());
+
+  list.RemoveLast();
+  list.RemoveLast();
+  list.RemoveLast();
+
+  EXPECT_EQ(kMagicNumberOne, list[0]->get_value());
+  EXPECT_EQ(kMagicNumberTwo, list[1]->get_value());
+  EXPECT_EQ(kMagicNumberThree, list[2]->get_value());
+}
+
+}  // namespace
+}  // namespace cc