Remove PRODUCT_STRING_PATH from chrome_constants.h on Windows.

chrome/chrome_common.gypi

 # 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.
 
 {
   'variables': {
     # File lists shared with GN build.
     'chrome_common_sources': [
       'common/all_messages.h',
       'common/attrition_experiments.h',
@@ skipping 638 matching lines @@
       ],
       'sources': [
         'common/image_decoder.mojom',
         'common/resource_usage_reporter.mojom',
       ],
       'dependencies': [
         '../mojo/mojo_public.gyp:mojo_cpp_bindings',
         '../skia/skia.gyp:skia_mojo',
       ],
     },
+    {
+      # GN version: //chrome/common:metrics_constants_util_win

[grt (UTC plus 2), 2016/04/15 15:29:32]

i think it's entirely appropriate to put this in an OS=="win" conditional

[gab, 2016/04/15 18:14:06]

Didn't initially think that was the right way but gave it a shot now in latest
patch set.

+      'target_name': 'metrics_constants_util_win',
+      'type': 'static_library',
+      'sources': [
+        'common/metrics_constants_util_win.cc',
+        'common/metrics_constants_util_win.h',
+      ],
+      'dependencies': [
+        'installer_util',
+        '../base/base.gyp:base',
+      ],
+    },
   ],
 }