Make base::Optional trivially destructible when possible.

base/template_util_unittest.cc

Index: base/template_util_unittest.cc
diff --git a/base/template_util_unittest.cc b/base/template_util_unittest.cc
index 057d7dc5bcf96646208654ec1a58a59ef8a67ed3..921596474b6d9a38991506396a1c64148025885d 100644
--- a/base/template_util_unittest.cc
+++ b/base/template_util_unittest.cc
@@ -111,5 +111,19 @@ static_assert(
 static_assert(std::is_same<underlying_type<ScopedEnum>::type, int>::value,
               "scoped enum defaults to int");
 
+struct TriviallyDestructible {
+  int field;
+};
+
+class NonTriviallyDestructible {
+  ~NonTriviallyDestructible() {}
+};
+
+static_assert(is_trivially_destructible<int>::value, "IsTriviallyDestructible");
+static_assert(is_trivially_destructible<TriviallyDestructible>::value,
+              "IsTriviallyDestructible");
+static_assert(!is_trivially_destructible<NonTriviallyDestructible>::value,
+              "IsTriviallyDestructible");
+
 }  // namespace
 }  // namespace base