Use 'cp' not 'copy' to copy in the FirstRun file, since the gyp msvs...

chrome/chrome.gyp

 # Copyright (c) 2009 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': {
     'chromium_code': 1,
     # Define the common dependencies that contain all the actual
     # Chromium functionality.  This list gets pulled in below by
     # the link of the actual chrome (or chromium) executable on
@@ skipping 2648 matching lines @@
               'message': 'Generating version information in <(_outputs)'
             },
             {
               'action_name': 'first_run',
               'inputs': [
                   'app/FirstRun',
               ],
               'outputs': [
                   '<(PRODUCT_DIR)/First Run',
               ],
-              'action': ['copy', '<@(_inputs)', '<@(_outputs)'],
+              'action': ['cp', '-f', '<@(_inputs)', '<@(_outputs)'],
               'message': 'Copy first run complete sentinel file',
             },
           ],
         },{  # 'OS!="win"
           'dependencies': [
             # On Linux and Mac, link the dependencies (libraries)
             # that make up actual Chromium functionality directly
             # into the executable.
             '<@(chromium_dependencies)',
           ],
@@ skipping 2086 matching lines @@
               # Use outputs of this action as inputs for the main target build.
               # Seems as a misnomer but makes this happy on Linux (scons).
               'process_outputs_as_sources': 1,
             },
           ],  # 'actions'
         },
       ]
     }],
   ],  # 'conditions'
 }