Add bisect config validation.

scripts/slave/recipe_modules/auto_bisect/example.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.
 
 import json
 
 DEPS = [
     'auto_bisect',
     'chromium_tests',
     'recipe_engine/json',
@@ skipping 324 matching lines @@
   """Returns a sample bisect config dict with some fields overridden."""
   example_config = {
       'test_type': 'perf',
       'command': (
           'src/tools/perf/run_benchmark -v --browser=release smoothness.'
           'tough_scrolling_cases'),
       'good_revision': '314015',
       'bad_revision': '314017',
       'metric': 'mean_input_event_latency/mean_input_event_latency',
       'repeat_count': '2',
+      'bug_id': '-1',
       'max_time_minutes': '5',
-      'bug_id': '',
       'gs_bucket': 'chrome-perf',
       'builder_host': 'master4.golo.chromium.org',
       'builder_port': '8341',
       'dummy_builds': 'True',
       'bypass_stats_check': 'True',
       'skip_gclient_ops': 'True',
-      'recipe_tester_name': 'linux_perf_tester'
+      'recipe_tester_name': 'linux_perf_tester',
   }
   if params:
     example_config.update(params)
   return example_config
 
 
 def _get_step_data_for_revision(api, revision_data, include_build_steps=True):
   """Generator that produces step patches for fake results."""
   commit_pos = revision_data['commit_pos']
   commit_hash = revision_data['hash']
@@ skipping 36 matching lines @@
           yield api.step_data(step_name, stdout=api.raw_io.output(file_hash))
         step_name = 'Expanding revision range for revision %s on depot %s'
         step_name %= (interval[-1], depot_name)
         stdout = api.json.output([(r, 0) for r in interval[:-1]])
         yield api.step_data(step_name, stdout=stdout)
 
     if 'cl_info' in revision_data:
       step_name = 'Reading culprit cl information.'
       stdout = api.json.output(revision_data['cl_info'])
       yield api.step_data(step_name, stdout=stdout)