Add base::MakeUnique to mirror C++14's std::make_unique.

base/memory/ptr_util_unittest.cc

Index: base/memory/ptr_util_unittest.cc
diff --git a/base/memory/ptr_util_unittest.cc b/base/memory/ptr_util_unittest.cc
index ecf99bff954a383cdc60d854c33c4c97b6cf1f4b..e5b7a15b1aed643be5168c66a8d4ca85204949ca 100644
--- a/base/memory/ptr_util_unittest.cc
+++ b/base/memory/ptr_util_unittest.cc
@@ -35,4 +35,34 @@ TEST(PtrUtilTest, WrapUnique) {
   EXPECT_EQ(0u, DeleteCounter::count());
 }
 
+TEST(PtrUtilTest, MakeUniqueScalar) {
+  auto s = MakeUnique<std::string>();
+  EXPECT_EQ("", *s);
+
+  auto s2 = MakeUnique<std::string>("test");
+  EXPECT_EQ("test", *s2);
+}
+
+TEST(PtrUtilTest, MakeUniqueScalarWithMoveOnlyType) {
+  using MoveOnly = std::unique_ptr<std::string>;
+  auto p = MakeUnique<MoveOnly>(MakeUnique<std::string>("test"));
+  EXPECT_EQ("test", **p);
+}
+
+TEST(PtrUtilTest, MakeUniqueArray) {
+  EXPECT_EQ(0u, DeleteCounter::count());
+  auto a = MakeUnique<DeleteCounter[]>(5);
+  EXPECT_EQ(5u, DeleteCounter::count());
+  a.reset();
+  EXPECT_EQ(0u, DeleteCounter::count());
+}
+
+#if 0
+// TODO(dcheng): Move this into a nocompile test.
+TEST(PtrUtilTest, MakeUniqueArrayWithKnownBounds) {
+  auto a = MakeUnique<DeleteCounter[1]>();
+  auto b = MakeUnique<DeleteCounter[1]>(1);
+}
+#endif
+
 }  // namespace base