install_toolchain: port to chromite python script.

BUG=chromium:875008
TEST=run_tests, precq
CQ-DEPEND=CL:1197212, CL:1197213, CL:1257188

Change-Id: Id43d0407706afb539473ce288211f66dfb6a707b
Reviewed-on: https://chromium-review.googlesource.com/1196837
Commit-Ready: Alex Klein <saklein@chromium.org>
Tested-by: Alex Klein <saklein@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
diff --git a/scripts/cros_generate_sysroot.py b/scripts/cros_generate_sysroot.py
index 1838388..8140718 100644
--- a/scripts/cros_generate_sysroot.py
+++ b/scripts/cros_generate_sysroot.py
@@ -18,6 +18,7 @@
 from chromite.lib import osutils
 from chromite.lib import sudo
 from chromite.lib import sysroot_lib
+from chromite.lib import toolchain
 
 DEFAULT_NAME = 'sysroot_%(package)s.tar.xz'
 PACKAGE_SEPARATOR = '/'
@@ -28,9 +29,9 @@
   """Parse args, and run environment-independent checks."""
   parser = commandline.ArgumentParser(description=__doc__)
   parser.add_argument('--board', required=True,
-                      help=('The board to generate the sysroot for.'))
+                      help='The board to generate the sysroot for.')
   parser.add_argument('--package', required=True,
-                      help=('The packages to generate the sysroot for.'))
+                      help='The packages to generate the sysroot for.')
   parser.add_argument('--deps-only', action='store_true',
                       default=False,
                       help='Build dependencies only.')
@@ -75,9 +76,7 @@
     # Create the sysroot's config.
     sysroot = sysroot_lib.Sysroot(self.sysroot)
     sysroot.WriteConfig(sysroot.GenerateBoardConfig(self.options.board))
-    cros_build_lib.RunCommand(
-        [os.path.join(constants.CROSUTILS_DIR, 'install_toolchain'),
-         '--noconfigure', '--sysroot', self.sysroot])
+    toolchain.InstallToolchain(sysroot, configure=False)
 
   def _InstallKernelHeaders(self):
     self._Emerge('sys-kernel/linux-headers')