Update from https://crrev.com/328418

build/gyp_chromium

 #!/usr/bin/env python
 
 # 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 script is wrapper for Chromium that adds some support for how GYP
 # is invoked by Chromium beyond what can be done in the gclient hooks.
 
 import argparse
@@ skipping 236 matching lines @@
   # assuming 'all.gyp' from the same directory as the script.
   if not gyp_file_specified:
     gyp_file = os.environ.get('CHROMIUM_GYP_FILE')
     if gyp_file:
       # Note that CHROMIUM_GYP_FILE values can't have backslashes as
       # path separators even on Windows due to the use of shlex.split().
       args.extend(shlex.split(gyp_file))
     else:
       args.append(os.path.join(script_dir, 'all.gyp'))
 
+  supplemental_includes = GetSupplementalFiles()
+  gyp_vars_dict = GetGypVars(supplemental_includes)
   # There shouldn't be a circular dependency relationship between .gyp files,
   # but in Chromium's .gyp files, on non-Mac platforms, circular relationships
   # currently exist.  The check for circular dependencies is currently
-  # bypassed on other platforms, but is left enabled on the Mac, where a
-  # violation of the rule causes Xcode to misbehave badly.
+  # bypassed on other platforms, but is left enabled on iOS, where a violation
+  # of the rule causes Xcode to misbehave badly.
   # TODO(mark): Find and kill remaining circular dependencies, and remove this
   # option.  http://crbug.com/35878.
   # TODO(tc): Fix circular dependencies in ChromiumOS then add linux2 to the
   # list.
-  if sys.platform not in ('darwin',):
+  if gyp_vars_dict.get('OS') != 'ios':
     args.append('--no-circular-check')
 
   # We explicitly don't support the make gyp generator (crbug.com/348686). Be
   # nice and fail here, rather than choking in gyp.
   if re.search(r'(^|,|\s)make($|,|\s)', os.environ.get('GYP_GENERATORS', '')):
     print 'Error: make gyp generator not supported (check GYP_GENERATORS).'
     sys.exit(1)
 
   # We explicitly don't support the native msvs gyp generator. Be nice and
   # fail here, rather than generating broken projects.
   if re.search(r'(^|,|\s)msvs($|,|\s)', os.environ.get('GYP_GENERATORS', '')):
     print 'Error: msvs gyp generator not supported (check GYP_GENERATORS).'
     print 'Did you mean to use the `msvs-ninja` generator?'
     sys.exit(1)
 
   # If CHROMIUM_GYP_SYNTAX_CHECK is set to 1, it will invoke gyp with --check
   # to enfore syntax checking.
   syntax_check = os.environ.get('CHROMIUM_GYP_SYNTAX_CHECK')
   if syntax_check and int(syntax_check):
     args.append('--check')
 
-  supplemental_includes = GetSupplementalFiles()
-  gyp_vars_dict = GetGypVars(supplemental_includes)
-
   # TODO(dmikurube): Remove these checks and messages after a while.
   if ('linux_use_tcmalloc' in gyp_vars_dict or
       'android_use_tcmalloc' in gyp_vars_dict):
     print '*****************************************************************'
     print '"linux_use_tcmalloc" and "android_use_tcmalloc" are deprecated!'
     print '-----------------------------------------------------------------'
     print 'You specify "linux_use_tcmalloc" or "android_use_tcmalloc" in'
     print 'your GYP_DEFINES. Please switch them into "use_allocator" now.'
     print 'See http://crbug.com/345554 for the details.'
     print '*****************************************************************'
@@ skipping 22 matching lines @@
 
   if not use_analyzer:
     vs2013_runtime_dll_dirs = vs_toolchain.SetEnvironmentAndGetRuntimeDllDirs()
     if vs2013_runtime_dll_dirs:
       x64_runtime, x86_runtime = vs2013_runtime_dll_dirs
       vs_toolchain.CopyVsRuntimeDlls(
         os.path.join(chrome_src, GetOutputDirectory()),
         (x86_runtime, x64_runtime))
 
   sys.exit(gyp_rc)