When updating expectations during wpt import, fill in results from missing builds.

third_party/WebKit/Tools/Scripts/webkitpy/w3c/wpt_expectations_updater.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.
 
 """Updates expectations and baselines when updating web-platform-tests.
 
 Specifically, this class fetches results from try bots for the current CL, then
 (1) downloads new baseline files for any tests that can be rebaselined, and
 (2) updates the generic TestExpectations file for any other failing tests.
 """
@@ skipping 394 matching lines @@
             _log.info('  %s', test)
         if tests_to_rebaseline:
             webkit_patch = self.host.filesystem.join(
                 self.finder.chromium_base(), self.finder.webkit_base(), self.finder.path_to_script('webkit-patch'))
             self.host.executive.run_command([
                 'python',
                 webkit_patch,
                 'rebaseline-cl',
                 '--verbose',
                 '--no-trigger-jobs',
+                '--fill-missing',
             ] + tests_to_rebaseline)
         return tests_results
 
     def get_tests_to_rebaseline(self, test_results):
         """Returns a list of tests to download new baselines for.
 
         Creates a list of tests to rebaseline depending on the tests' platform-
         specific results. In general, this will be non-ref tests that failed
         due to a baseline mismatch (rather than crash or timeout).
 
@@ skipping 21 matching lines @@
         if result['actual'] in ('CRASH', 'TIMEOUT', 'MISSING'):
             return False
         return True
 
     def is_reference_test(self, test_path):
         """Checks whether a given file is a testharness.js test."""
         return bool(self.port.reference_files(test_path))
 
     def _get_try_bots(self):
         return self.host.builders.all_try_builder_names()