recipe engine: add a hook for initializing recipe module with injected deps

recipe_engine/recipe_api.py

-# Copyright 2013-2015 The Chromium Authors. All rights reserved.
+# 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.
 
 from __future__ import absolute_import
 import contextlib
 import keyword
 import re
 import types
 
 from functools import wraps
@@ skipping 351 matching lines @@
     # If we're the 'root' api, inject directly into 'self'.
     # Otherwise inject into 'self.m'
     self.m = self if module is None else ModuleInjectionSite(self)
 
     # If our module has a test api, it gets injected here.
     self.test_api = None
 
     # Config goes here.
     self.c = None
 
+  def initialize(self):
+    """
+    Initializes the recipe module after it has been instantiated with all
+    dependencies injected and available.
+    """
+    pass
+
   def get_config_defaults(self):  # pylint: disable=R0201
     """
     Allows your api to dynamically determine static default values for configs.
     """
     return {}
 
   def make_config(self, config_name=None, optional=False, **CONFIG_VARS):
     """Returns a 'config blob' for the current API."""
     return self.make_config_params(config_name, optional, **CONFIG_VARS)[0]
 
@@ skipping 253 matching lines @@
     """
     Gets the BoundProperty version of this Property. Requires a name.
     """
     return BoundProperty(
         self._default, self.help, self.kind, name, property_type, module,
         self.param_name)
 
 class UndefinedPropertyException(TypeError):
   pass