Remove support for Ubuntu/Precise 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.
 
 """Install Debian sysroots for building chromium.
 """
 
 # The sysroot is needed to ensure that binaries that get built will run on
 # the oldest stable version of Debian that we currently support.
@@ skipping 104 matching lines @@
   Another reason we're installing this by default is so that developers can
   compile and run on our supported platforms without having to worry about
   flipping things back and forth and whether the sysroots have been downloaded
   or not.
   """
   InstallDefaultSysrootForArch(host_arch)
 
   if host_arch == 'amd64':
     InstallDefaultSysrootForArch('i386')
 
-  # Desktop Chromium OS builds require the precise sysroot.
-  # TODO(thomasanderson): only download this when the GN arg target_os
-  # == 'chromeos', when the functionality to perform the check becomes
-  # available.
-  InstallSysroot('Precise', 'amd64')
-
   # If we can detect a non-standard target_arch such as ARM or MIPS,
   # then install the sysroot too.  Don't attempt to install arm64
   # since this is currently and android-only architecture.
   target_arch = DetectTargetArch()
   if target_arch and target_arch not in (host_arch, 'i386'):
     InstallDefaultSysrootForArch(target_arch)
 
 
 def main(args):
   parser = optparse.OptionParser('usage: %prog [OPTIONS]', description=__doc__)
@@ skipping 89 matching lines @@
   with open(stamp, 'w') as s:
     s.write(url)
 
 
 if __name__ == '__main__':
   try:
     sys.exit(main(sys.argv[1:]))
   except Error as e:
     sys.stderr.write(str(e) + '\n')
     sys.exit(1)