cc: Add RandomAccessListContainer, which has more restricted API.

cc/base/list_container_unittest.cc

Index: cc/base/list_container_unittest.cc
diff --git a/cc/base/list_container_unittest.cc b/cc/base/list_container_unittest.cc
index be0b2b75b4e34824e13e04b024dc430ec80f7fbb..174d606b8afb45edfece8dbf64b8c048590f0dc4 100644
--- a/cc/base/list_container_unittest.cc
+++ b/cc/base/list_container_unittest.cc
@@ -86,7 +86,7 @@ class SimpleDerivedElement : public DerivedElement {
  public:
   ~SimpleDerivedElement() override {}
   void set_value(int val) { value = val; }
-  int get_value() { return value; }
+  int get_value() const { return value; }
 
  private:
   int value;
@@ -1201,5 +1201,35 @@ TEST(ListContainerTest, GetCapacityInBytes) {
   }
 }
 
+TEST(RandomAccessListContainerTest, RandomAccess) {
+  RandomAccessListContainer<SimpleDerivedElement> list(
+      LargestDerivedElementSize(), 1);
+
+  list.AllocateAndConstruct<SimpleDerivedElementConstructMagicNumberOne>();
+  list.AllocateAndConstruct<SimpleDerivedElementConstructMagicNumberTwo>();
+  list.AllocateAndConstruct<SimpleDerivedElementConstructMagicNumberThree>();
+  list.AllocateAndConstruct<SimpleDerivedElementConstructMagicNumberOne>();
+  list.AllocateAndConstruct<SimpleDerivedElementConstructMagicNumberTwo>();
+  list.AllocateAndConstruct<SimpleDerivedElementConstructMagicNumberThree>();
+
+  EXPECT_EQ(kMagicNumberToUseForSimpleDerivedElementOne, list[0]->get_value());
+  EXPECT_EQ(kMagicNumberToUseForSimpleDerivedElementTwo, list[1]->get_value());
+  EXPECT_EQ(kMagicNumberToUseForSimpleDerivedElementThree,
+            list[2]->get_value());
+  EXPECT_EQ(kMagicNumberToUseForSimpleDerivedElementOne, list[3]->get_value());
+  EXPECT_EQ(kMagicNumberToUseForSimpleDerivedElementTwo, list[4]->get_value());
+  EXPECT_EQ(kMagicNumberToUseForSimpleDerivedElementThree,
+            list[5]->get_value());
+
+  list.RemoveLast();
+  list.RemoveLast();
+  list.RemoveLast();
+
+  EXPECT_EQ(kMagicNumberToUseForSimpleDerivedElementOne, list[0]->get_value());
+  EXPECT_EQ(kMagicNumberToUseForSimpleDerivedElementTwo, list[1]->get_value());
+  EXPECT_EQ(kMagicNumberToUseForSimpleDerivedElementThree,
+            list[2]->get_value());
+}
+
 }  // namespace
 }  // namespace cc