Update NaCl ARM build flags now that gcc used as default compiler.

build/download_nacl_toolchains.py

 #!/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.
 
 """Shim to run nacl toolchain download script only if there is a nacl dir."""
 
 import os
 import sys
 
@@ skipping 11 matching lines @@
     print "Can't find '%s'" % download_script
     print 'Presumably you are intentionally building without NativeClient.'
     print 'Skipping NativeClient toolchain download.'
     sys.exit(0)
   sys.path.insert(0, nacl_build_dir)
   import download_toolchains
 
   # TODO (robertm): Finish getting PNaCl ready for prime time.
   # BUG:
   # We remove this --optional-pnacl argument, and instead replace it with
-  # --no-pnacl for most cases.  However, if the bot name is the pnacl_sdk
+  # --no-pnacl for most cases.  However, if the bot name is an sdk
   # bot then we will go ahead and download it.  This prevents increasing the
   # gclient sync time for developers, or standard Chrome bots.
   if '--optional-pnacl' in args:
     args.remove('--optional-pnacl')
-    # By default we don't use PNaCl toolchain yet, unless on ARM, where
-    # there is no other toolchain to build untrusted code at the moment.
-    # So analyze if we're building for ARM, or on SDK buildbot.
-    # TODO(olonho): we need to invent more reliable way to get build
-    # configuration info, to know if we're building for ARM.
     use_pnacl = False
-    if 'target_arch=arm' in os.environ.get('GYP_DEFINES', ''):
-      use_pnacl = True
     buildbot_name = os.environ.get('BUILDBOT_BUILDERNAME', '')
-    if buildbot_name.find('pnacl') >= 0 and  buildbot_name.find('sdk') >= 0:
+    if 'pnacl' in buildbot_name and 'sdk' in buildbot_name:
       use_pnacl = True
     if use_pnacl:
       print '\n*** DOWNLOADING PNACL TOOLCHAIN ***\n'
     else:
       args.append('--no-pnacl')
 
+  # Only download the ARM gcc toolchain if we are building for ARM
+  # TODO(olonho): we need to invent more reliable way to get build
+  # configuration info, to know if we're building for ARM.
+  if 'target_arch=arm' in os.environ.get('GYP_DEFINES', ''):
+      args.append('--arm-untrusted')
+
   # Append the name of the file to use as a version and hash source.
   # NOTE:  While not recommended, it is possible to redirect this file to
   # a chrome location to avoid branching NaCl if just a toolchain needs
   # to be bumped.
-  args.append(os.path.join(nacl_dir,'TOOL_REVISIONS'))
+  args.append(os.path.join(nacl_dir, 'TOOL_REVISIONS'))
 
   download_toolchains.main(args)
   return 0
 
 
 if __name__ == '__main__':
   sys.exit(Main(sys.argv[1:]))