Add gcl-reset option.

Review URL: http://codereview.chromium.org/647063

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@39457 0039d316-1c4b-4281-b951-d872f2087c98

gclient.py

@@ -125,6 +125,7 @@ Valid options:
   --deps PLATFORM(S)      : sync deps for the given platform(s), or 'all'
   --verbose               : output additional diagnostics
   --head                  : update to latest revision, instead of last good revision
+  --reset                 : resets any local changes before updating (git only)
 
 Examples:
   gclient %(cmd)s
@@ -1129,6 +1130,9 @@ def Main(argv):
                            help=("(update/sync only) sync deps for the "
                                  "specified (comma-separated) platform(s); "
                                  "'all' will sync all platforms"))
+  option_parser.add_option("", "--reset", action="store_true", default=False,
+                           help=("(update/sync only) resets any local changes "
+                                 "before updating (git only)"))
   option_parser.add_option("", "--spec", default=None,
                            help=("(config only) create a gclient file "
                                  "containing the provided string"))

gclient_scm.py

@@ -231,7 +231,7 @@ class GitWrapper(SCMWrapper, scm.GIT):
     self._Run(['remote', 'update'], redirect_stdout=False)
     files = self._Run(['diff', new_base, '--name-only']).split()
     file_list.extend([os.path.join(self.checkout_path, f) for f in files])
-    if options.force:
+    if options.force or options.reset:
       self._Run(['reset', '--hard', merge_base], redirect_stdout=False)
     try:
       self._Run(['rebase', '-v', '--onto', new_base, merge_base, cur_branch],