Fix for rebaseline-cl --only-changed-tests: use hard-coded constant layout test dir.

third_party/WebKit/Tools/Scripts/webkitpy/tool/commands/rebaseline_cl.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 command to fetch new baselines from try jobs for a Rietveld issue.
 
 This command interacts with the Rietveld API to get information about try jobs
 with layout test results.
 """
 
@@ skipping 140 matching lines @@
             only_changed_tests: Whether to only include baselines for tests that
                are changed in this CL. If False, all new baselines for failing
                tests will be downloaded, even for tests that were not modified.
 
         Returns:
             A dict containing information about which new baselines to download.
         """
         builds_to_tests = self._builds_to_tests(issue_number)
         if only_changed_tests:
             files_in_cl = self.rietveld.changed_files(issue_number)
-            finder = WebKitFinder(self._tool.filesystem)
-            tests_in_cl = [finder.layout_test_name(f) for f in files_in_cl]
+            # Note, in the changed files list from Rietveld, paths always
+            # use / as the separator, and they're always relative to repo root.
+            # TODO(qyearsley): Do this without using a hard-coded constant.
+            test_base = 'third_party/WebKit/LayoutTests/'
+            tests_in_cl = [f[len(test_base):] for f in files_in_cl if f.startswith(test_base)]
         result = {}
         for build, tests in builds_to_tests.iteritems():
             for test in tests:
                 if only_changed_tests and test not in tests_in_cl:
                     continue
                 if test not in result:
                     result[test] = {}
                 result[test][build] = BASELINE_SUFFIX_LIST
         return result
 
@@ skipping 24 matching lines @@
     @staticmethod
     def _log_test_prefix_list(test_prefix_list):
         """Logs the tests to download new baselines for."""
         if not test_prefix_list:
             _log.info('No tests to rebaseline; exiting.')
             return
         _log.info('Tests to rebaseline:')
         for test, builds in test_prefix_list.iteritems():
             builds_str = ', '.join(sorted('%s (%s)' % (b.builder_name, b.build_number) for b in builds))
             _log.info('  %s: %s', test, builds_str)