In rebaseline-cl: add option to only rebaseline tests changed in the CL.

third_party/WebKit/Tools/Scripts/webkitpy/common/net/rietveld.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.
 
 """Utility functions to communicate with Rietveld."""
 
 import json
 import logging
 import urllib2
 
@@ skipping 30 matching lines @@
     jobs = []
     for job in patchset_data['try_job_results']:
         if job['builder'] not in builder_names:
             continue
         jobs.append(Build(
             builder_name=job['builder'],
             build_number=job['buildnumber']))
     return filter_latest_jobs(jobs)
 
 
+def changed_files(issue_number, web):
+    """Lists the files included in a CL, or None if this can't be determined.
+
+    File paths are sorted and relative to the repository root.
+    """
+    try:
+        url = _latest_patchset_url(issue_number, web)
+        issue_data = _get_json(url, web)
+        return sorted(issue_data['files'])
+    except (urllib2.URLError, ValueError, KeyError):
+        _log.warning('Failed to list changed files for issue %s.', issue_number)
+        return None
+
+
 def _latest_patchset_url(issue_number, web):
     issue_data = _get_json(_issue_url(issue_number), web)
     latest_patchset_number = issue_data["patchsets"][-1]
     return _patchset_url(issue_number, latest_patchset_number)
 
 
 def _get_json(url, web):
     """Fetches JSON from a URL, and logs errors if the request was unsuccessful.
 
     Raises:
@@ skipping 40 matching lines @@
     )]
 
 
 def get_latest_try_job_results(issue_number, web):
     url = _latest_patchset_url(issue_number, web)
     patchset_data = _get_json(url, web)
     results = {}
     for job in patchset_data['try_job_results']:
         results[job['builder']] = job['result']
     return results