Cleanup logic for deciding when to install linux sysroot

build/linux/sysroot_scripts/install-sysroot.py

 #!/usr/bin/env python
 # Copyright (c) 2013 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.
 
 # Script to install a Debian Wheezy sysroot for making official Google Chrome
 # Linux builds.
 # The sysroot is needed to make Chrome work for Debian Wheezy.
 # This script can be run manually but is more often run as part of gclient
 # hooks. When run from hooks this script should be a no-op on non-linux
@@ skipping 76 matching lines @@
   elif detected_host_arch == 'arm':
     return 'arm'
   elif detected_host_arch == 'mips':
     return 'mips'
   else:
     print "Unknown host arch: %s" % detected_host_arch
 
   return None
 
 
+def UsingSysroot(target_arch, gyp_defines):
+  # ChromeOS uses a chroot, so doesn't need a sysroot
+  if 'chromeos=1' in gyp_defines:
+    return False
+
+  # When cross-compiling we always use a sysroot
+  if target_arch in ('arm', 'mips', 'ia32'):
+    return True
+
+  # Setting use_sysroot=1 GYP_DEFINES forces the use of the sysroot even
+  # when not cross compiling
+  if 'use_sysroot=1' in gyp_defines:
+    return True
+
+  # Official builds always use the sysroot.
+  if 'branding=Chrome' in gyp_defines and 'buildtype=Official' in gyp_defines:
+    return True
+
+  return False
+
+
 def main():
   if options.running_as_hook and not sys.platform.startswith('linux'):
     return 0
 
   gyp_defines = os.environ.get('GYP_DEFINES', '')
 
   if options.arch:
     target_arch = options.arch
   else:
     target_arch = DetectArch(gyp_defines)
     if not target_arch:
       print 'Unable to detect host architecture'
       return 1
 
-  if options.running_as_hook and target_arch != 'arm' and target_arch != 'mips':
-    # When run from runhooks, only install the sysroot for an Official Chrome
-    # Linux build, except on ARM where we always use a sysroot.
-    skip_if_defined = ['branding=Chrome', 'buildtype=Official']
-    skip_if_undefined = ['chromeos=1']
-    for option in skip_if_defined:
-      if option not in gyp_defines:
-        return 0
-    for option in skip_if_undefined:
-      if option in gyp_defines:
-        return 0
+  if options.running_as_hook and not UsingSysroot(target_arch, gyp_defines):
+    return 0
 
   # The sysroot directory should match the one specified in build/common.gypi.
   # TODO(thestig) Consider putting this else where to avoid having to recreate
   # it on every build.
   linux_dir = os.path.dirname(SCRIPT_DIR)
   if target_arch == 'amd64':
     sysroot = os.path.join(linux_dir, SYSROOT_DIR_AMD64)
     tarball_filename = TARBALL_AMD64
     tarball_sha1sum = TARBALL_AMD64_SHA1SUM
     revision = REVISION_AMD64
@@ skipping 52 matching lines @@
   parser = optparse.OptionParser('usage: %prog [OPTIONS]')
   parser.add_option('--running-as-hook', action='store_true',
                     default=False, help='Used when running from gclient hooks.'
                                         ' In this mode the sysroot will only '
                                         'be installed for official Linux '
                                         'builds or ARM Linux builds')
   parser.add_option('--arch', type='choice', choices=valid_archs,
                     help='Sysroot architecture: %s' % ', '.join(valid_archs))
   options, _ = parser.parse_args()
   sys.exit(main())