GN: Build app snapshots for the SDK tools.

tools/gn.py

 #!/usr/bin/env python
 # Copyright 2016 The Dart project 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 argparse
 import multiprocessing
 import os
 import subprocess
 import sys
@@ skipping 102 matching lines @@
   gn_args['is_clang'] = args.clang and has_clang
 
   gn_args['is_asan'] = args.asan and gn_args['is_clang']
 
   if args.target_sysroot:
     gn_args['target_sysroot'] = args.target_sysroot
 
   if args.toolchain_prefix:
     gn_args['toolchain_prefix'] = args.toolchain_prefix
 
+  # If we are on ia32 or cross-compiling, use app snapshots without code for the SDK.
+  if arch == 'ia32' or gn_args['target_cpu'] != gn_args['host_cpu']:
+    gn_args['dart_app_snapshot_kind'] = 'app-after-run'
+  else:
+    gn_args['dart_app_snapshot_kind'] = 'app-jit-after-run'
+
   goma_dir = os.environ.get('GOMA_DIR')
   goma_home_dir = os.path.join(os.getenv('HOME', ''), 'goma')
   if args.goma and goma_dir:
     gn_args['use_goma'] = True
     gn_args['goma_dir'] = goma_dir
   elif args.goma and os.path.exists(goma_home_dir):
     gn_args['use_goma'] = True
     gn_args['goma_dir'] = goma_home_dir
   else:
     gn_args['use_goma'] = False
@@ skipping 180 matching lines @@
       return 1
 
   endtime = time.time()
   if args.verbose:
     print ("GN Time: %.3f seconds" % (endtime - starttime))
   return 0
 
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv))