Enabling /ZW (CompileAsWinRT) option for msvs

test/win/gyptest-cl-compile-as-winrt.py

+# Copyright (c) 2016 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import TestGyp
+
+import os
+import sys
+
+if (sys.platform == 'win32' and
+    int(os.environ.get('GYP_MSVS_VERSION', 0)) >= 2015):
+  test = TestGyp.TestGyp(formats=['msvs'])
+
+  CHDIR = 'compiler-flags'
+
+  test.run_gyp('compile-as-winrt.gyp', chdir=CHDIR)
+
+  test.build('compile-as-winrt.gyp', 'test-compile-as-winrt', chdir=CHDIR)
+
+  test.pass_test()