recipes: Switch from 3 ways for requesting clobber builds to 1

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 recipe_engine.config import config_item_context, ConfigGroup
 from recipe_engine.config import Dict, List, Single, Static, Set, BadConf
 from recipe_engine.config_types import Path
 
@@ skipping 738 matching lines @@
   gyp_defs['fastbuild'] = 1
 
 @config_ctx(includes=['ninja', 'static_library', 'msvs2015'])
 def chromium_pgo_base(c):
   c.gyp_env.GYP_DEFINES['buildtype'] = 'Official'
   c.gyp_env.GYP_DEFINES['use_goma'] = 0
   fastbuild(c, invert=True)
   c.compile_py.default_targets = ['chrome']
 
 #### 'Full' configurations
-@config_ctx(includes=['chromium_pgo_base'])
+@config_ctx(includes=['chromium_pgo_base', 'clobber'])
 def chromium_pgo_instrument(c):
   c.gyp_env.GYP_DEFINES['chrome_pgo_phase'] = 1
   # Some of the binaries needed by the PGO gets copied into the build directory
   # during the build, we need to augment the PATH variable so it can find them
   # during the profiling step.
   c.env.PATH.extend([c.build_dir.join(c.build_config_fs)])
 
 @config_ctx(includes=['chromium_pgo_base'])
 def chromium_pgo_optimize(c):
   c.gyp_env.GYP_DEFINES['chrome_pgo_phase'] = 2
@@ skipping 31 matching lines @@
   c.gyp_env.GYP_DEFINES['internal_gles2_conform_tests'] = 1
 
 @config_ctx()
 def build_angle_deqp_tests(c):
   c.gyp_env.GYP_DEFINES['build_angle_deqp_tests'] = 1
 
 @config_ctx()
 def force_mac_toolchain(c):
   c.env.FORCE_MAC_TOOLCHAIN = 1
   c.gyp_env.FORCE_MAC_TOOLCHAIN = 1