chromite recipe: Add warm cache flag support.

scripts/slave/recipe_modules/chromite/config.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 os
 import types
 
 from recipe_engine.config import config_item_context, ConfigGroup
 from recipe_engine.config import Dict, Single, Set
 
@@ skipping 41 matching lines @@
 
       # If True, add cbuildbot flag: '--clobber'.
       clobber = Single(bool, empty_val=CBB_CLOBBER),
 
       # The (optional) configuration repository to use.
       config_repo = Single(basestring),
 
       # This disables Chromite bootstrapping by omitting the explicit "--branch"
       # argument.
       disable_bootstrap = Single(bool),
+
+      # Whether this Chromite version supports warm cache.
+      # https://chromium-review.googlesource.com/#/c/348011
+      supports_repo_cache = Single(bool),
     ),
 
     # A list of branches whose Chromite version is "old". Old Chromite
     # buildbot commands reside in the "buildbot" subdirectory of the Chromite
     # repository instead of the "bin".
     old_chromite_branches = Set(basestring),
 
     # A list of branches whose builders should not use a shared buildroot.
     non_shared_root_branches = Set(basestring),
 
     # A list of branches whose builders checkout Chrome from SVN instead of Git.
     chrome_svn_branches = Set(basestring),
+
+    # Directory where a warm repo cache is stored. If set, and if the current
+    # build supports a warm cache, this will be used to bootstrap the Chromite
+    # checkout.
+    repo_cache_dir = Single(basestring)
   )
 
 config_ctx = config_item_context(BaseConfig)
 
 
 @config_ctx()
 def base(c):
   c.repositories['tryjob'] = []
   c.repositories['chromium'] = []
   c.repositories['cros_manifest'] = []
+  c.repo_cache_dir = '/var/cache/chrome-infra/ccompute-setup/cros-internal'
 
   c.old_chromite_branches.update((
     'firmware-uboot_v2-1299.B',
     'factory-1412.B',
   ))
   c.non_shared_root_branches.update(c.old_chromite_branches)
   c.non_shared_root_branches.update((
     'factory-2305.B',
   ))
   c.chrome_svn_branches.update((
@@ skipping 24 matching lines @@
 
 @config_ctx(group='master', includes=['external'])
 def master_chromiumos_chromium(c):
   c.use_chrome_version = True
   c.cbb.builddir = 'shared_external'
 
 
 @config_ctx(group='master', includes=['external'])
 def master_chromiumos(c):
   c.cbb.builddir = 'external_master'
+  c.cbb.supports_repo_cache = True
 
 @config_ctx()
 def chromiumos_paladin(c):
   c.read_cros_manifest = True
 
 @config_ctx(group='master', includes=['external'])
 def chromiumos_tryserver(c):
   c.cbb.disable_bootstrap = True
 
 @config_ctx()
 def chromiumos_coverage_test(c):
   c.use_chrome_version = True
   c.read_cros_manifest = True
   c.cbb.chrome_rev = 'stable'