Add numeric_cast for checked integral narrowing casts

base/safe_numerics_unittest.nc

+// Copyright (c) 2013 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 "base/safe_numerics.h"
+
+namespace base {
+namespace internal {
+
+void NoFloatingPoint {
+  IsValidNumericCast<float>(0.0);
+  IsValidNumericCast<double>(0.0f);
+  IsValidNumericCast<int>(DBL_MAX);
+}
+
+}  // namespace internal
+}  // namespace base