In rebaseline, include build number information with "test_prefix_list" dicts.

third_party/WebKit/Tools/Scripts/webkitpy/tool/commands/rebaseline_from_try_jobs.py

Index: third_party/WebKit/Tools/Scripts/webkitpy/tool/commands/rebaseline_from_try_jobs.py
diff --git a/third_party/WebKit/Tools/Scripts/webkitpy/tool/commands/rebaseline_from_try_jobs.py b/third_party/WebKit/Tools/Scripts/webkitpy/tool/commands/rebaseline_from_try_jobs.py
index d8617bb75d0a1d182c0f4749e4ec234b664e69d2..28f21214c2f737037769ea7e286e4f425bd86602 100644
--- a/third_party/WebKit/Tools/Scripts/webkitpy/tool/commands/rebaseline_from_try_jobs.py
+++ b/third_party/WebKit/Tools/Scripts/webkitpy/tool/commands/rebaseline_from_try_jobs.py
@@ -76,27 +76,26 @@ class RebaselineFromTryJobs(AbstractParallelRebaselineCommand):
 
     def _test_prefix_list(self, issue_number):
         """Returns a collection of test, builder and file extensions to get new baselines for."""
-        builders_to_tests = self._builders_to_tests(issue_number)
+        builds_to_tests = self._builds_to_tests(issue_number)
         result = {}
-        for builder, tests in builders_to_tests.iteritems():
+        for build, tests in builds_to_tests.iteritems():
             for test in tests:
                 if test not in result:
                     result[test] = {}
-                # TODO(qyearsley): Consider using TestExpectations.suffixes_for_test_result.
-                result[test][builder] = BASELINE_SUFFIX_LIST
+                result[test][build] = BASELINE_SUFFIX_LIST
         return result
 
-    def _builders_to_tests(self, issue_number):
+    def _builds_to_tests(self, issue_number):
         """Fetches a list of try bots, and for each, fetches tests with new baselines."""
         _log.debug('Getting results for Rietveld issue %d.' % issue_number)
         try_jobs = latest_try_jobs(issue_number, self._try_bots(), self.web)
         if not try_jobs:
             _log.debug('No try job results for builders in: %r.' % (self._try_bots(),))
-        builders_to_tests = {}
+        builds_to_tests = {}
         for job in try_jobs:
             test_results = self._unexpected_mismatch_results(job)
-            builders_to_tests[job.builder_name] = sorted(r.test_name() for r in test_results)
-        return builders_to_tests
+            builds_to_tests[(job.builder_name, job.build_number)] = sorted(r.test_name() for r in test_results)
+        return builds_to_tests
 
     def _try_bots(self):
         """Retuns a collection of try bot builders to fetch results for."""
@@ -119,5 +118,6 @@ class RebaselineFromTryJobs(AbstractParallelRebaselineCommand):
             _log.info('No tests to rebaseline.')
             return
         _log.info('Tests to rebaseline:')
-        for test, builders in test_prefix_list.iteritems():
-            _log.info('  %s: %s', test, ', '.join(sorted(builders)))
+        for test, builds in test_prefix_list.iteritems():
+            builds_str = ', '.join(sorted('%s (%s)' % b for b in builds))
+            _log.info('  %s: %s', test, builds_str)