Make VS2015 component builds work on swarming.

build/isolate.gypi

 # Copyright (c) 2012 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 file is meant to be included into a target to provide a rule
 # to "build" .isolate files into a .isolated file.
 #
 # To use this, create a gyp target with the following form:
 # 'conditions': [
 #   ['test_isolation_mode != "noop"', {
@@ skipping 101 matching lines @@
         }],
         ["test_isolation_mode == 'prepare'", {
           'outputs': [
             '<(PRODUCT_DIR)/<(RULE_INPUT_ROOT).isolated.gen.json',
           ],
         }, {
           'outputs': [
             '<(PRODUCT_DIR)/<(RULE_INPUT_ROOT).isolated',
           ],
         }],
+        ['OS=="win"', {
+          'action': [
+            '--config-variable', 'msvs_version=<(MSVS_VERSION)',
+          ],
+        }, {
+          'action': [
+            '--config-variable', 'msvs_version=0',
+          ],
+        }],
       ],
     },
   ],
 }