run cygwin mount setup in runhooks, and remove some references to it

build/grit_target.gypi

 # Copyright (c) 2011 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 that will have one or more
 # uses of grit_action.gypi. To use this the following variables need to be
 # defined:
 #   grit_out_dir: string: the output directory path
 
 # NOTE: This file is optional, not all targets that use grit include it, some
 # do their own custom directives instead.
 {
   'conditions': [
     # If the target is a direct binary, it needs to be able to find the header,
     # otherwise it probably a supporting target just for grit so the include
     # dir needs to be set on anything that depends on this action.
     ['_type=="executable" or _type=="shared_library" or \
       _type=="loadable_module" or _type=="static_library"', {
       'include_dirs': [
         '<(grit_out_dir)',
       ],
     }, {
       'direct_dependent_settings': {
         'include_dirs': [
           '<(grit_out_dir)',
         ],
       },
     }],
-    ['OS=="win"', {
-      'dependencies': ['<(DEPTH)/build/win/system.gyp:cygwin'],
-    }],
   ],
 }