Add apply_gerrit_ref to bot_update api

recipe_modules/tryserver/api.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.
 
 import collections
 import contextlib
 import hashlib
+import os
+import sys
+import uuid
 
 from recipe_engine import recipe_api
 
 
 PATCH_STORAGE_RIETVELD = 'rietveld'
+PATCH_STORAGE_GERRIT = 'gerrit'
 PATCH_STORAGE_GIT = 'git'
 PATCH_STORAGE_SVN = 'svn'
 
 
 class TryserverApi(recipe_api.RecipeApi):
   def __init__(self, *args, **kwargs):
     super(TryserverApi, self).__init__(*args, **kwargs)
     self._failure_reasons = []
 
   @property
@@ skipping 106 matching lines @@
   def maybe_apply_issue(self, cwd=None, authentication=None):
     """If we're a trybot, apply a codereview issue.
 
     Args:
       cwd: If specified, apply the patch from the specified directory.
       authentication: authentication scheme whenever apply_issue.py is called.
         This is only used if the patch comes from Rietveld. Possible values:
         None, 'oauth2' (see also api.rietveld.apply_issue.)
     """
     storage = self.determine_patch_storage()
-
     if storage == PATCH_STORAGE_RIETVELD:
       return self.m.rietveld.apply_issue(
           self.m.rietveld.calculate_issue_root(),
           authentication=authentication)
+    elif storage == PATCH_STORAGE_GERRIT:

[tandrii(chromium), 2016/08/19 14:00:04]

Hm, can you move this condition instead to skia recipe just to get going?

[rmistry, 2016/08/19 14:36:08]

That makes sense. Will do.

+      patch_project = (self.m.properties.get('patch_project') or
+                       self.m.properties.get('project'))
+      return self.m.bot_update.apply_gerrit_ref(
+          gerrit_repo=self.m.properties.get('repository') or 'origin',
+          gerrit_ref=self.m.properties.get('event.patchSet.ref'),
+          root=str(self.m.path['slave_build'].join(patch_project)))
     elif storage == PATCH_STORAGE_SVN:
       return self.apply_from_svn(cwd)
     elif storage == PATCH_STORAGE_GIT:
       return self.apply_from_git(cwd)
     else:
       # Since this method is "maybe", we don't raise an Exception.
       pass
 
   def get_files_affected_by_patch(self, patch_root=None, **kwargs):
     """Returns list of paths to files affected by the patch.
@@ skipping 150 matching lines @@
     result = self.m.python(
         'parse description', self.package_repo_resource('git_footers.py'),
         args=['--json', self.m.json.output()],
         stdin=self.m.raw_io.input(data=patch_text))
     return result.json.output
 
   def get_footer(self, tag, patch_text=None):
     """Gets a specific tag from a CL description"""
     return self.get_footers(patch_text).get(tag, [])