Orphan headers should check only added files

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 605 matching lines @@
   try:
     sys.path = sys.path + [input_api.os_path.join(
         input_api.PresubmitLocalPath(), 'tools_webrtc', 'presubmit_checks_lib')]
     from check_orphan_headers import GetBuildGnPathFromFilePath
     from check_orphan_headers import IsHeaderInBuildGn
   finally:
     # Restore sys.path to what it was before.
     sys.path = original_sys_path
 
   for f in input_api.AffectedSourceFiles(input_api.FilterSourceFile):
-    if f.LocalPath().endswith('.h'):
+    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