Add Presubmit for changing CSD proto definitions without changing the WebUI logging

Bug: 852922
Change-Id: I2db33fb3dd5f13dda3420965e72d8aa92695ffe5
Reviewed-on: https://chromium-review.googlesource.com/1103539
Commit-Queue: Daniel Rubery <drubery@chromium.org>
Reviewed-by: Varun Khaneja <vakh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#568086}

components/safe_browsing/proto/PRESUBMIT.py

+# Copyright 2018 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.
+
+def CheckChangeOnUpload(input_api, output_api):
+  # Warn if the proto file is not modified without also modifying
+  # the WebUI.
+  proto_path = 'components/safe_browsing/proto/csd.proto'
+  web_ui_path = 'components/safe_browsing/web_ui/safe_browsing_ui.cc'
+
+  if proto_path in input_api.change.LocalPaths() and \
+      not web_ui_path in input_api.change.LocalPaths():
+    return [
+        output_api.PresubmitPromptWarning(
+            'You modified the one or more of the CSD protos in: \n'
+            '  ' + proto_path + '\n'
+            'without changing the WebUI in: \n'
+            '  ' + web_ui_path + '\n')
+    ]
+  return []