Add GN (the build tool) to the chromium.linux buildbots and try jobs

scripts/slave/recipe_modules/chromium/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 pipes
 
 from slave.recipe_config import config_item_context, ConfigGroup
 from slave.recipe_config import Dict, Single, Static, Set, BadConf
 from slave.recipe_config_types import Path
 
@@ skipping 21 matching lines @@
     compile_py = ConfigGroup(
       default_targets = Set(basestring),
       build_tool = Single(basestring),
       compiler = Single(basestring, required=False),
       mode = Single(basestring, required=False),
       goma_dir = Single(Path, required=False),
       clobber = Single(bool, empty_val=False, required=False, hidden=False),
     ),
     gyp_env = ConfigGroup(
       GYP_CROSSCOMPILE = Single(int, jsonish_fn=str, required=False),
+      GYP_CHROMIUM_NO_ACTION = Single(int, jsonish_fn=str, required=False),
       GYP_DEFINES = Dict(equal_fn, ' '.join, (basestring,int,Path)),
       GYP_GENERATORS = Set(basestring, ','.join),
       GYP_GENERATOR_FLAGS = Dict(equal_fn, ' '.join, (basestring,int)),
       GYP_MSVS_VERSION = Single(basestring, required=False),
     ),
     build_dir = Single(Path),
 
     # Some platforms do not have a 1:1 correlation of BUILD_CONFIG to what is
     # passed as --target on the command line.
     build_config_fs = Single(basestring),
@@ skipping 271 matching lines @@
 def android(c):
   gyp_defs = c.gyp_env.GYP_DEFINES
   gyp_defs['fastbuild'] = 1
   gyp_defs['OS'] = c.TARGET_PLATFORM
 
 @config_ctx(includes=['ninja', 'shared_library', 'jsonclang'])
 def codesearch(c):
   gyp_defs = c.gyp_env.GYP_DEFINES
   gyp_defs['fastbuild'] = 1