Extract functions from path recipe module so that step can depend on it

scripts/slave/recipe_modules/zip/example.py

 # Copyright 2014 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.
 
 DEPS = [
+  'file',
   'path',
   'platform',
   'step',
   'zip',
 ]
 
 def GenSteps(api):
   # Prepare files.
   temp = api.path.mkdtemp('zip-example')
   api.step('touch a', ['touch', temp.join('a')])
   api.step('touch b', ['touch', temp.join('b')])
-  api.path.makedirs('mkdirs', temp.join('sub', 'dir'))
+  api.file.makedirs('mkdirs', temp.join('sub', 'dir'))
   api.step('touch c', ['touch', temp.join('sub', 'dir', 'c')])
 
   # Build zip using 'zip.directory'.
   api.zip.directory('zipping', temp, temp.join('output.zip'))
 
   # Build a zip using ZipPackage api.
   package = api.zip.make_package(temp, temp.join('more.zip'))
   package.add_file(package.root.join('a'))
   package.add_file(package.root.join('b'))
   package.add_directory(package.root.join('sub'))
   package.zip('zipping more')
 
   # Coverage for 'output' property.
   api.step('report', ['echo', package.output])
 
   # Unzip the package.
   api.zip.unzip('unzipping', temp.join('output.zip'), temp.join('output'))
   # List unzipped content.
   api.step('listing', ['find'], cwd=temp.join('output'))
   # Clean up.
-  api.path.rmtree('cleanup', temp)
+  api.file.rmtree('cleanup', temp)
 
 
 def GenTests(api):
   for platform in ('linux', 'win', 'mac'):
     yield api.test(platform) + api.platform.name(platform)