gsutil: use depot_tools.gsutil_py_path instead of path['depot_tools']

scripts/slave/recipe_modules/gsutil/api.py

 # Copyright 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.
 
 import re
 
 from recipe_engine import recipe_api
 
 class GSUtilApi(recipe_api.RecipeApi):
   def __call__(self, cmd, name=None, use_retry_wrapper=True, version=None,
@@ skipping 10 matching lines @@
     Arguments:
       cmd: list of (string) arguments to pass to gsutil.
            Include gsutil-level options first (see 'gsutil help options').
       name: the (string) name of the step to use.
             Defaults to the first non-flag token in the cmd.
     """
     if not name:
       name = (t for t in cmd if not t.startswith('-')).next()
     full_name = 'gsutil ' + name
 
-    gsutil_path = self.m.path['depot_tools'].join('gsutil.py')
+    gsutil_path = self.m.depot_tools.gsutil_py_path

[tandrii(chromium), 2016/06/03 13:28:17]

why not move this whole recipe into depot_tools? Seems to me like a cleaner
idea, albeit requiring ~3 cls.

[tandrii(chromium), 2016/06/03 13:48:58]

discussed in IM: we postpone the actual refactoring moving this whole
recipe_module to depot_tools where it belongs. Reason - it's risky, and even
though inevitable, we can avoid this risk for now.

     cmd_prefix = []
 
     if use_retry_wrapper:
       # We pass the real gsutil_path to the wrapper so it doesn't have to do
       # brittle path logic.
       cmd_prefix = ['--', gsutil_path]
       gsutil_path = self.resource('gsutil_wrapper.py')
 
     if version:
       cmd_prefix.extend(['--force-version', version])
@@ skipping 160 matching lines @@
         'Content-Language',
         'Content-MD5',
         'Content-Type',
     ):
       return name
 
     # Add provider prefix
     if not provider_prefix:
       provider_prefix = 'x-goog-meta'
     return '%s-%s' % (provider_prefix, name)