Update from https://crrev.com/327068

build/gyp_helper.py

 # Copyright (c) 2012 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.
 
 # This file helps gyp_chromium and landmines correctly set up the gyp
 # environment from chromium.gyp_env on disk
 
 import os
 
 SCRIPT_DIR = os.path.dirname(os.path.realpath(__file__))
 CHROME_SRC = os.path.dirname(SCRIPT_DIR)
 
 
 def apply_gyp_environment_from_file(file_path):
   """Reads in a *.gyp_env file and applies the valid keys to os.environ."""
   if not os.path.exists(file_path):
     return
   with open(file_path, 'rU') as f:
     file_contents = f.read()
   try:
     file_data = eval(file_contents, {'__builtins__': None}, None)
   except SyntaxError, e:
     e.filename = os.path.abspath(file_path)
     raise
   supported_vars = (
       'CC',
       'CC_wrapper',
+      'CC.host_wrapper',
       'CHROMIUM_GYP_FILE',
       'CHROMIUM_GYP_SYNTAX_CHECK',
       'CXX',
       'CXX_wrapper',
+      'CXX.host_wrapper',
       'GYP_DEFINES',
       'GYP_GENERATOR_FLAGS',
       'GYP_CROSSCOMPILE',
       'GYP_GENERATOR_OUTPUT',
       'GYP_GENERATORS',
       'GYP_INCLUDE_FIRST',
       'GYP_INCLUDE_LAST',
       'GYP_MSVS_VERSION',
   )
   for var in supported_vars:
@@ skipping 15 matching lines @@
         os.environ[var] = result
       else:
         os.environ[var] = file_val
 
 
 def apply_chromium_gyp_env():
   if 'SKIP_CHROMIUM_GYP_ENV' not in os.environ:
     # Update the environment based on chromium.gyp_env
     path = os.path.join(os.path.dirname(CHROME_SRC), 'chromium.gyp_env')
     apply_gyp_environment_from_file(path)