Update message for Gerrit git cl --no-squash users.

git_cl.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.
 
 # Copyright (C) 2008 Evan Martin <martine@danga.com>
 
 """A git-command for integrating reviews on Rietveld and Gerrit."""
 
 from distutils.version import LooseVersion
@@ skipping 2321 matching lines @@
       if reply.lower().startswith('y'):
         gclient_utils.rm_file_or_tree(hook)
         print('Gerrit commit-msg hook removed.')
       else:
         print('OK, will keep Gerrit commit-msg hook in place.')
 
   def CMDUploadChange(self, options, args, change):
     """Upload the current branch to Gerrit."""
     if options.squash and options.no_squash:
       DieWithError('Can only use one of --squash or --no-squash')
+    # TODO(tandrii): remove this by June 20.
+    if (RunGit(['config', '--bool', 'gerrit.squash-uploads'],
+               error_ok=True).strip() != 'false' and not options.squash and
+        not options.no_squash):
+        print('\n\nHi! You are using git cl upload in --no-squash mode.\n'
+              'Chrome infrastructure wants to make --squash the default.\n'
+              'To ensure that --no-squash is still the default for YOU do:\n'
+              '   git config --bool gerrit.squash-uploads false\n'
+              'See https://goo.gl/dnK2gV (use chromium.org account!) and '
+              'let us know what you think. Thanks!\n'
+              'BUG: http://crbug.com/611892\n\n')
+
     options.squash = ((settings.GetSquashGerritUploads() or options.squash) and

[tandrii(chromium), 2016/06/10 15:33:03]

this is the other point at which it's called.
Yes, redundant. 
But, as you can see above, my condition is very specific - i really want to
detect that a user hasn't set the option to false, but GetSquashGerritUploads()
would return default (false now, true later).

                       not options.no_squash)
+
     # We assume the remote called "origin" is the one we want.
     # It is probably not worthwhile to support different workflows.
     gerrit_remote = 'origin'
 
     remote, remote_branch = self.GetRemoteBranch()
     branch = GetTargetRef(remote, remote_branch, options.target_branch,
                           pending_prefix='')
 
     if options.squash:
       self._GerritCommitMsgHookCheck(offer_removal=not options.force)
@@ skipping 509 matching lines @@
   """
   if not settings.GetIsGerrit():
     return
   src = 'https://gerrit-review.googlesource.com/tools/hooks/commit-msg'
   dst = os.path.join(settings.GetRoot(), '.git', 'hooks', 'commit-msg')
   if not os.access(dst, os.X_OK):
     if os.path.exists(dst):
       if not force:
         return
     try:
-      print(
-          'WARNING: installing Gerrit commit-msg hook.\n'
-          '         This behavior of git cl will soon be disabled.\n'
-          '         See bug http://crbug.com/579176.')
       urlretrieve(src, dst)
       if not hasSheBang(dst):
         DieWithError('Not a script: %s\n'
                      'You need to download from\n%s\n'
                      'into .git/hooks/commit-msg and '
                      'chmod +x .git/hooks/commit-msg' % (dst, src))
       os.chmod(dst, stat.S_IRUSR | stat.S_IWUSR | stat.S_IXUSR)
     except Exception:
       if os.path.exists(dst):
         os.remove(dst)
@@ skipping 2137 matching lines @@
 if __name__ == '__main__':
   # These affect sys.stdout so do it outside of main() to simplify mocks in
   # unit testing.
   fix_encoding.fix_encoding()
   setup_color.init()
   try:
     sys.exit(main(sys.argv[1:]))
   except KeyboardInterrupt:
     sys.stderr.write('interrupted\n')
     sys.exit(1)