GN iOS build fixes.

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 glob
@@ skipping 215 matching lines @@
   # These string arguments get passed directly as GN strings.
   for v in ['android_src', 'arm_float_abi', 'ios_deployment_target',
             'ios_sdk_path', 'windows_sdk_path']:
     if v in vars_dict:
       gn_args += ' ' + v + '=' + EscapeStringForGN(vars_dict[v])
 
   # gomadir is renamed goma_dir in the GN build.
   if 'gomadir' in vars_dict:
     gn_args += ' goma_dir=%s' % EscapeStringForGN(vars_dict['gomadir'])
 
-  # Clear the "use_ios_simulator" flag if the ios_sdk_path is set and is
-  # not a simulator SDK. This duplicates code done in GYP's xcode emulation.
+  # Set the "use_ios_simulator" flag if the ios_sdk_path is set.
   if 'ios_sdk_path' in vars_dict:
-    if not os.path.basename(vars_dict['ios_sdk_path']).lower().startswith(
+    if os.path.basename(vars_dict['ios_sdk_path']).lower().startswith(
         'iphonesimulator'):
+      gn_args += ' use_ios_simulator=true'
+    else:
       gn_args += ' use_ios_simulator=false'
 
-
   # These arguments get passed directly as integers (avoiding the quoting and
   # escaping of the string ones above).
   for v in ['arm_version']:
     if v in vars_dict:
       gn_args += ' %s=%s' % (v, vars_dict[v])
 
   # Some other flags come from GYP environment variables.
   gyp_msvs_version = os.environ.get('GYP_MSVS_VERSION', '')
   if gyp_msvs_version:
     gn_args += ' visual_studio_version=' + EscapeStringForGN(gyp_msvs_version)
@@ skipping 238 matching lines @@
   # rather than a separate runhooks step so that any environment modifications
   # from above are picked up.
   print 'Running build/landmines.py...'
   subprocess.check_call(
       [sys.executable, os.path.join(script_dir, 'landmines.py')])
 
   if vs2013_runtime_dll_dirs:
     CopyVsRuntimeDlls(GetOutputDirectory(), vs2013_runtime_dll_dirs)
 
   sys.exit(gyp_rc)