Fix autoroller in accordance to upstream change

tools_webrtc/autoroller/roll_deps.py

 #!/usr/bin/env python
 # Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
 #
 # Use of this source code is governed by a BSD-style license
 # that can be found in the LICENSE file in the root of the source
 # tree. An additional intellectual property rights grant can be found
 # in the file PATENTS.  All contributing project authors may
 # be found in the AUTHORS file in the root of the source tree.
 
 """Script to automatically roll dependencies in the WebRTC DEPS file."""
@@ skipping 32 matching lines @@
 ROLL_BRANCH_NAME = 'roll_chromium_revision'
 
 SCRIPT_DIR = os.path.dirname(os.path.abspath(__file__))
 CHECKOUT_SRC_DIR = os.path.realpath(os.path.join(SCRIPT_DIR, os.pardir,
                                                  os.pardir))
 CHECKOUT_ROOT_DIR = os.path.realpath(os.path.join(CHECKOUT_SRC_DIR, os.pardir))
 
 sys.path.append(os.path.join(CHECKOUT_SRC_DIR, 'build'))
 import find_depot_tools
 find_depot_tools.add_depot_tools_to_path()
-from gclient import GClientKeywords
 
 CLANG_UPDATE_SCRIPT_URL_PATH = 'tools/clang/scripts/update.py'
 CLANG_UPDATE_SCRIPT_LOCAL_PATH = os.path.join(CHECKOUT_SRC_DIR, 'tools',
                                               'clang', 'scripts', 'update.py')
 
 DepsEntry = collections.namedtuple('DepsEntry', 'path url revision')
 ChangedDep = collections.namedtuple('ChangedDep',
                                     'path url current_rev new_rev')
 
 class RollError(Exception):
   pass
 
 
+def VarLookup(local_scope):
+  return lambda var_name: local_scope['vars'][var_name]
+
+
 def ParseDepsDict(deps_content):
   local_scope = {}
-  var = GClientKeywords.VarImpl({}, local_scope)
   global_scope = {
-    'Var': var.Lookup,
+    'Var': VarLookup(local_scope),
     'deps_os': {},
   }
   exec(deps_content, global_scope, local_scope)
   return local_scope
 
 
 def ParseLocalDepsFile(filename):
   with open(filename, 'rb') as f:
     deps_content = f.read()
   return ParseDepsDict(deps_content)
@@ skipping 399 matching lines @@
     logging.info("No DEPS changes detected, skipping CL creation.")
   else:
     _LocalCommit(commit_msg, opts.dry_run)
     _UploadCL(opts.dry_run, opts.rietveld_email)
     _SendToCQ(opts.dry_run, opts.skip_cq)
   return 0
 
 
 if __name__ == '__main__':
   sys.exit(main())