Treat std::atomic_int as a trivial class member when checking for non-trivial classes.

tools/clang/plugins/tests/trivial_ctor.cpp

Index: tools/clang/plugins/tests/trivial_ctor.cpp
diff --git a/tools/clang/plugins/tests/trivial_ctor.cpp b/tools/clang/plugins/tests/trivial_ctor.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..e24bb6f1e0329bf3f6204750e596a4ddc8f62ddc
--- /dev/null
+++ b/tools/clang/plugins/tests/trivial_ctor.cpp
@@ -0,0 +1,22 @@
+// Copyright (c) 2016 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 "trivial_ctor.h"
+
+// Due to https://bugs.chromium.org/p/chromium/issues/detail?id=663463, we treat
+// templated classes/structs as non-trivial, even if they really are trivial.
+// Thus, classes that have such a class/struct as a member get flagged as being
+// themselves non-trivial, even if (like |MySpinLock|) they are. Special-case
+// [std::]atomic_int.
+class TrivialTemplateOK {
+ public:
+
+ private:
+  MySpinLock lock_;
+};
+
+int main() {
+  TrivialTemplateOK one;
+  return 0;
+}