Increasing perf swarming job expiration to 4 hours.

tools/perf/generate_perf_json.py

 #!/usr/bin/env python
 # 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.
 
 """Script to generate chromium.perf.json and chromium.perf.fyi.json in
 the src/testing/buildbot directory. Maintaining these files by hand is
 too unwieldy.
 """
 
@@ skipping 287 matching lines @@
   # --device=android
 
   step_name = benchmark_name
   if browser == 'reference':
     test_args.append('--output-trace-tag=_ref')
     step_name += '.reference'
   swarming = {
     # Always say this is true regardless of whether the tester
     # supports swarming. It doesn't hurt.
     'can_use_on_swarming_builders': True,
+    'expiration': 14400,
     'dimension_sets': swarming_dimensions
   }
 
   result = {
     'args': test_args,
     'isolate_name': 'telemetry_perf_tests',
     'name': step_name,
     'override_compile_targets': ['telemetry_perf_tests'],
     'swarming': swarming,
   }
@@ skipping 87 matching lines @@
 
 def main():
   waterfall = get_waterfall_config()
   fyi_waterfall = get_fyi_waterfall_config()
   generate_all_tests(fyi_waterfall, True)
   generate_all_tests(waterfall, False)
   return 0
 
 if __name__ == "__main__":
   sys.exit(main())