Refactor WPT Export to ensure only one PR in flight at a time

third_party/WebKit/Tools/Scripts/webkitpy/w3c/sync_wpt.py

 # Copyright 2016 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.
 
 """A script for exporting and importing changes between the Chromium repo
 and the web-platform-tests repo.
 
 TODO(jeffcarp): does not handle reverted changes right now
 TODO(jeffcarp): it also doesn't handle changes to -expected.html files
 TODO(jeffcarp): Currently this script only does export; also add an option
@@ skipping 34 matching lines @@
     exportable_commits = chromium_wpt.exportable_commits_since(chromium_commit.sha)
 
     if exportable_commits:
         _log.info('Found %s exportable commits in chromium:', len(exportable_commits))
         for commit in exportable_commits:
             _log.info('- %s %s', commit, chromium_wpt.subject(commit))
     else:
         _log.info('No exportable commits found in Chromium, stopping.')
         return
 
+    if options.status:
+        return
+
+    # should no longer iterate through all of them
+    # should at most one of these per process:
+    # - create a PR
+    # - check a PR status (and merge if green)
     for commit in exportable_commits:
         _log.info('Uploading %s', chromium_wpt.subject(commit))
         chromium_commit = ChromiumCommit(host, sha=commit)
 
         patch = chromium_wpt.format_patch(commit)
         message = chromium_wpt.message(commit)
 
         local_wpt.create_branch_with_patch(branch_name, message, patch)
 
         github.create_pr(
             local_branch_name='chromium-try-{}'.format(commit),
             desc_title=chromium_commit.subject(),
             body=chromium_commit.body())
 
 
 def parse_args():
     parser = argparse.ArgumentParser(description='WPT Sync')
     parser.add_argument('--no-fetch', action='store_true')
+    parser.add_argument('--status', action='store_true')
     return parser.parse_args()