Add constexpr TaskTraits constructor.

base/task_scheduler/task_traits_unittest.nc

+// Copyright 2017 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.
+
+// This is a "No Compile Test" suite.
+// http://dev.chromium.org/developers/testing/no-compile-tests
+
+#include "base/task_scheduler/task_traits.h"
+
+namespace base {
+
+#if defined(NCTEST_TASK_TRAITS_MULTIPLE_MAY_BLOCK)  // [r"Multiple arguments of the same type were provided to the constructor of TaskTraits."]
+constexpr TaskTraits traits = {MayBlock(), MayBlock()};
+#elif defined(NCTEST_TASK_TRAITS_MULTIPLE_WITH_BASE_SYNC_PRIMITIVES)  // [r"Multiple arguments of the same type were provided to the constructor of TaskTraits."]
+constexpr TaskTraits traits = {WithBaseSyncPrimitives(),
+                               WithBaseSyncPrimitives()};
+#elif defined(NCTEST_TASK_TRAITS_MULTIPLE_TASK_PRIORITY)  // [r"Multiple arguments of the same type were provided to the constructor of TaskTraits."]
+constexpr TaskTraits traits = {TaskPriority::BACKGROUND,
+                               TaskPriority::USER_BLOCKING};
+#elif defined(NCTEST_TASK_TRAITS_MULTIPLE_SHUTDOWN_BEHAVIOR)  // [r"Multiple arguments of the same type were provided to the constructor of TaskTraits."]
+constexpr TaskTraits traits = {TaskShutdownBehavior::BLOCK_SHUTDOWN,
+                               TaskShutdownBehavior::BLOCK_SHUTDOWN};
+#elif defined(NCTEST_TASK_TRAITS_MULTIPLE_SAME_TYPE_MIX)  // [r"Multiple arguments of the same type were provided to the constructor of TaskTraits."]
+constexpr TaskTraits traits = {TaskShutdownBehavior::BLOCK_SHUTDOWN,
+                               MayBlock(),
+                               TaskShutdownBehavior::CONTINUE_ON_SHUTDOWN};
+#elif defined(NCTEST_TASK_TRAITS_INVALID_TYPE)  // [r"no matching constructor for initialization of 'const base::TaskTraits'"]
+constexpr TaskTraits traits = {TaskShutdownBehavior::BLOCK_SHUTDOWN, true};
+#endif
+
+}  // namespace base