Add `--revert` option to patch_updater.py.

git-svn-id: https://chromiumembedded.googlecode.com/svn/trunk@1811 5089003a-bbd8-11dd-ad1f-f1f9622dbc98

tools/patch_updater.py

@@ -47,8 +47,16 @@ parser = OptionParser(description=disc)
 parser.add_option('--resave',
                   action='store_true', dest='resave', default=False,
                   help='re-save existing patch files to pick up manual changes')
+parser.add_option('--revert',
+                  action='store_true', dest='revert', default=False,
+                  help='revert all changes from existing patch files')
 (options, args) = parser.parse_args()
 
+if options.resave and options.revert:
+  print 'Invalid combination of options.'
+  parser.print_help(sys.stderr)
+  sys.exit()
+
 # The CEF root directory is the parent directory of _this_ script.
 cef_dir = os.path.abspath(os.path.join(os.path.dirname(__file__), os.pardir))
 src_dir = os.path.join(cef_dir, os.pardir)
@@ -102,6 +110,7 @@ for patch in patches:
         if result['out'] != '':
           sys.stdout.write(result['out'])
 
+      if not options.revert:
         # Apply the patch file.
         msg('Applying patch to %s' % patch_root_abs)
         result = exec_cmd('patch -p0', patch_root_abs, patch_file)
@@ -113,6 +122,7 @@ for patch in patches:
                patch['name'])
           continue
 
+    if not options.revert:
       # Re-create the patch file.
       msg('Saving changes to %s' % patch_file)
       patch_paths_str = ' '.join(patch_paths)