Update from https://crrev.com/333737

testing/variations/PRESUBMIT.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.
+
+"""Presubmit script validating field trial configs.
+
+See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts
+for more details on the presubmit API built into depot_tools.
+"""
+
+def ValidateData(json_data, file_path, message_type):
+  """Validates the format of a fieldtrial configuration.
+
+  Args:
+    json_data: Parsed JSON object representing the fieldtrial config.
+    file_path: String representing the path to the JSON file.
+    message_type: Type of message from |output_api| to return in the case of
+        errors/warnings.
+
+  Returns:
+    A list of |message_type| messages. In the case of all tests passing with no
+    warnings/errors, this will return [].
+  """
+  if not isinstance(json_data, dict):
+    return [message_type(
+        'Malformed config file %s: Expecting dict' % file_path)]
+  for (study, groups) in json_data.iteritems():
+    if not isinstance(study, unicode):
+      return [message_type(
+          'Malformed config file %s: Expecting keys to be string, got %s'
+          % (file_path, type(study)))]
+    if not isinstance(groups, list):
+      return [message_type(
+          'Malformed config file %s: Expecting list for study %s'
+          % (file_path, study))]
+    for group in groups:
+      if not isinstance(group, dict):
+        return [message_type(
+            'Malformed config file %s: Expecting dict for group in '
+            'Study[%s]' % (file_path, study))]
+      if not 'group_name' in group or not isinstance(group['group_name'],
+          unicode):
+        return [message_type(
+            'Malformed config file %s: Missing valid group_name for group'
+            ' in Study[%s]' % (file_path, study))]
+      if 'params' in group:
+        params = group['params']
+        if not isinstance(params, dict):
+          return [message_type(
+              'Malformed config file %s: Invalid params for Group[%s]'
+              ' in Study[%s]' % (file_path, group['group_name'],
+              study))]
+        for (key, value) in params.iteritems():
+          if not isinstance(key, unicode) or not isinstance(value,
+              unicode):
+            return [message_type(
+                'Malformed config file %s: Invalid params for Group[%s]'
+                ' in Study[%s]' % (file_path, group['group_name'],
+                study))]
+  return []
+
+def CommonChecks(input_api, output_api):
+  affected_files = input_api.AffectedFiles(
+      include_deletes=False,
+      file_filter=lambda x: x.LocalPath().endswith('.json'))
+  for f in affected_files:
+    contents = input_api.ReadFile(f)
+    try:
+      json_data = input_api.json.loads(contents)
+      result =  ValidateData(json_data, f.LocalPath(),
+          output_api.PresubmitError)
+      if len(result):
+        return result
+    except ValueError:
+      return [output_api.PresubmitError(
+          'Malformed JSON file: %s' % f.LocalPath())]
+  return []
+
+def CheckChangeOnUpload(input_api, output_api):
+  return CommonChecks(input_api, output_api)
+
+def CheckChangeOnCommit(input_api, output_api):
+  return CommonChecks(input_api, output_api)