update presubmit to know about include/private

PRESUBMIT.py

 # Copyright (c) 2013 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.
 
 
 """Top-level presubmit script for Skia.
 
 See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts
 for more details about the presubmit API built into gcl.
 """
@@ skipping 261 matching lines @@
 
   For public API files make sure there is an LGTM from the list of owners in
   PUBLIC_API_OWNERS.
   """
   results = []
   requires_owner_check = False
   for affected_file in input_api.AffectedFiles():
     affected_file_path = affected_file.LocalPath()
     file_path, file_ext = os.path.splitext(affected_file_path)
     # We only care about files that end in .h and are under the top-level
-    # include dir.
-    if file_ext == '.h' and 'include' == file_path.split(os.path.sep)[0]:
+    # include dir, but not include/private.
+    if (file_ext == '.h' and
+        'include' == file_path.split(os.path.sep)[0] and
+        'private' not in file_path):
       requires_owner_check = True
 
   if not requires_owner_check:
     return results
 
   lgtm_from_owner = False
   issue = input_api.change.issue
   if issue and input_api.rietveld:
     issue_properties = input_api.rietveld.get_issue_properties(
         issue=int(issue), messages=True)
@@ skipping 27 matching lines @@
       for message in messages:
         if (message['sender'] in PUBLIC_API_OWNERS and
             'lgtm' in message['text'].lower()):
           # Found an lgtm in a message from an owner.
           lgtm_from_owner = True
           break
 
   if not lgtm_from_owner:
     results.append(
         output_api.PresubmitError(
-            'Since the CL is editing public API, you must have an LGTM from '
-            'one of: %s' % str(PUBLIC_API_OWNERS)))
+            "If this CL adds to or changes Skia's public API, you need an LGTM "
+            "from any of %s.  If this CL only removes from or doesn't change "
+            "Skia's public API, please add a short note to the CL saying so "
+            "and add one of those reviewers on a TBR= line.  If you don't know "
+            "if this CL affects Skia's public API, treat it like it does."
+            % str(PUBLIC_API_OWNERS)))
   return results
 
 
 def PostUploadHook(cl, change, output_api):
   """git cl upload will call this hook after the issue is created/modified.
 
   This hook does the following:
   * Adds a link to preview docs changes if there are any docs changes in the CL.
   * Adds 'NOTRY=true' if the CL contains only docs changes.
   * Adds 'NOTREECHECKS=true' for non master branch changes since they do not
@@ skipping 142 matching lines @@
     state and an error if it is in 'Closed' state.
   """
   results = []
   results.extend(_CommonChecks(input_api, output_api))
   results.extend(
       _CheckTreeStatus(input_api, output_api, json_url=(
           SKIA_TREE_STATUS_URL + '/banner-status?format=json')))
   results.extend(_CheckLGTMsForPublicAPI(input_api, output_api))
   results.extend(_CheckOwnerIsInAuthorsFile(input_api, output_api))
   return results