Adding api option to download test data before a perf run.

scripts/slave/recipe_modules/v8/example.py

 # Copyright 2014 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.
 
 DEPS = [
   'bot_update',
   'json',
   'path',
   'perf_dashboard',
   'properties',
@@ skipping 11 matching lines @@
   api.v8.revision_number = '12345'
   api.v8.revision = 'deadbeef'
   perf_config = {
     'example1': {
       'name': 'Example1',
       'json': 'example1.json',
     },
     'example2': {
       'name': 'Example2',
       'json': 'example2.json',
+      'download_test': 'foo',
     }
   }
   api.v8.runperf(api.v8.perf_tests, perf_config, category='ia32',
                  extra_flags=['--flag1', '--flag2'])
   output1 = api.path['slave_build'].join('test_output1.json')
   output2 = api.path['slave_build'].join('test_output2.json')
   results = api.v8.merge_perf_results(output1, output2)
   api.step('do something with the results', ['echo', results['res']])
 
 
 def GenTests(api):
   yield (
     api.test('perf_failures') +
     api.v8(perf_failures=True) +
     api.step_data('Example1', retcode=1) +
     api.properties.generic(mastername='Fake_Master',
                            buildername='Fake Builder',
                            revision='20123')
   )
   yield (
     api.test('forced_build') +
     api.properties.generic(mastername='Fake_Master',
                            buildername='Fake Builder') +
     api.step_data(
       'merge perf results',
       stdout=api.json.output({'res': 'the result'}))
   )