[WPT import] Add a flag to upload but not submit CL

We used to have only one flag, --auto-update, which controls both
uploading and landing the import CL. This makes testing new setup of the
bot (i.e. LUCI in this case) hard.

This change adds one more flag, --auto-upload, to exercise more steps
(namely uploading and rebaselining), which will be used on the
experimental LUCI builder.

Bug: 790503
Change-Id: I4ce07fc9ddf15a34c9cb25ba4723d250cad26977
Reviewed-on: https://chromium-review.googlesource.com/c/1277587
Commit-Queue: Robert Ma <robertma@chromium.org>
Reviewed-by: Quinten Yearsley <qyearsley@chromium.org>
Cr-Commit-Position: refs/heads/master@{#599197}

third_party/blink/tools/blinkpy/w3c/test_importer.py

@@ -85,6 +85,10 @@ class TestImporter(object):
             # Print out the full output when executive.run_command fails.
             self.host.executive.error_output_limit = None
 
+        if options.auto_update and options.auto_upload:
+            _log.error('--auto-upload and --auto-update cannot be used together.')
+            return 1
+
         if not self.checkout_is_okay():
             return 1
 
@@ -164,7 +168,7 @@ class TestImporter(object):
         self._commit_changes(commit_message)
         _log.info('Changes imported and committed.')
 
-        if not options.auto_update:
+        if not options.auto_upload and not options.auto_update:
             return 0
 
         self._upload_cl()
@@ -173,6 +177,9 @@ class TestImporter(object):
         if not self.update_expectations_for_cl():
             return 1
 
+        if not options.auto_update:
+            return 0
+
         if not self.run_commit_queue_for_cl():
             return 1
 
@@ -276,6 +283,9 @@ class TestImporter(object):
             '--ignore-exportable-commits', action='store_true',
             help='do not check for exportable commits that would be clobbered')
         parser.add_argument('-r', '--revision', help='target wpt revision')
+        parser.add_argument(
+            '--auto-upload', action='store_true',
+            help='upload a CL, update expectations, but do NOT trigger CQ')
         parser.add_argument(
             '--auto-update', action='store_true',
             help='upload a CL, update expectations, and trigger CQ')