Only run _IsBuildFailureUniqueAcrossPlatforms if need_new_try_job is true.

appengine/findit/waterfall/try_job_util.py

 # Copyright 2015 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.
 
 from datetime import datetime
 import logging
 
 from google.appengine.ext import ndb
 
 from common import appengine_util
@@ skipping 300 matching lines @@
     need_new_try_job, last_pass = _CheckFailureForTryJobKey(
         master_name, builder_name, build_number,
         failure_result_map, TryJobType.COMPILE, failed_steps['compile'])
   else:
     try_job_type = TryJobType.TEST
     targeted_tests, need_new_try_job, last_pass = (
         _CheckIfNeedNewTryJobForTestFailure(
             'step', master_name, builder_name, build_number, failure_result_map,
             failed_steps))
 
-  # TODO(josiahk): Integrate this into need_new_try_job boolean
-  _IsBuildFailureUniqueAcrossPlatforms(
-      master_name, builder_name, build_number, build_failure_type,
-      builds[str(build_number)]['blame_list'], failed_steps, signals,
-      heuristic_result)
 
   need_new_try_job = (
       need_new_try_job and ReviveOrCreateTryJobEntity(
           master_name, builder_name, build_number, force_try_job))
 
+  # TODO(josiahk): Integrate _IsBuildFailureUniqueAcrossPlatforms() into
+  # need_new_try_job boolean
+  if need_new_try_job:
+    _IsBuildFailureUniqueAcrossPlatforms(
+        master_name, builder_name, build_number, build_failure_type,
+        builds[str(build_number)]['blame_list'], failed_steps, signals,
+        heuristic_result)
+
   return need_new_try_job, last_pass, try_job_type, targeted_tests
 
 
 def _GetFailedTargetsFromSignals(signals, master_name, builder_name):
   compile_targets = []
 
   if not signals or 'compile' not in signals:
     return compile_targets
 
   if signals['compile'].get('failed_output_nodes'):
@@ skipping 90 matching lines @@
               pipeline.pipeline_status_path, try_job_type)
     else:  # pragma: no cover
       logging_str = (
           'Try job was scheduled for build %s, %s, %s: %s because of %s '
           'failure.') % (
               master_name, builder_name, build_number,
               pipeline.pipeline_status_path, try_job_type)
     logging.info(logging_str)
 
   return failure_result_map