Remove CheckChangeHasTestField PRESUBMIT check.

PRESUBMIT.py

 # Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
 #
 # Use of this source code is governed by a BSD-style license
 # that can be found in the LICENSE file in the root of the source
 # tree. An additional intellectual property rights grant can be found
 # in the file PATENTS.  All contributing project authors may
 # be found in the AUTHORS file in the root of the source tree.
 
 import json
 import os
@@ skipping 580 matching lines @@
 def CheckChangeOnCommit(input_api, output_api):
   results = []
   results.extend(_CommonChecks(input_api, output_api))
   results.extend(_VerifyNativeApiHeadersListIsValid(input_api, output_api))
   results.extend(input_api.canned_checks.CheckOwners(input_api, output_api))
   results.extend(input_api.canned_checks.CheckChangeWasUploaded(
       input_api, output_api))
   results.extend(input_api.canned_checks.CheckChangeHasDescription(
       input_api, output_api))
   results.extend(_CheckChangeHasBugField(input_api, output_api))
-  results.extend(input_api.canned_checks.CheckChangeHasTestField(
-      input_api, output_api))
   results.extend(input_api.canned_checks.CheckTreeIsOpen(
       input_api, output_api,
       json_url='http://webrtc-status.appspot.com/current?format=json'))
   return results
 
 
 def _CheckOrphanHeaders(input_api, output_api):
   # We need to wait until we have an input_api object and use this
   # roundabout construct to import prebubmit_checks_lib because this file is
   # eval-ed and thus doesn't have __file__.
@@ skipping 14 matching lines @@
     if f.LocalPath().endswith('.h') and f.Action() == 'A':
       file_path = os.path.abspath(f.LocalPath())
       root_dir = os.getcwd()
       gn_file_path = GetBuildGnPathFromFilePath(file_path, os.path.exists,
                                                 root_dir)
       in_build_gn = IsHeaderInBuildGn(file_path, gn_file_path)
       if not in_build_gn:
         results.append(output_api.PresubmitError(error_msg.format(
             file_path, gn_file_path)))
   return results