MD History: Lazily load element files which are not needed for first paint

chrome/browser/resources/md_history/PRESUBMIT.py

 # Copyright 2016 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.
 
 import os.path
 import time
 
 def CheckChangeOnUpload(input_api, output_api):
   """Warn when changing md_history without vulcanizing."""
 
   def _is_md_history_file(path):
     return (path.startswith('chrome/browser/resources/md_history') and
             (not path.endswith('externs.js')) and
-            (not path.endswith('app.crisper.js')) and
-            (not path.endswith('app.vulcanized.html')) and
+            (not path.endswith('crisper.js')) and
+            (not path.endswith('vulcanized.html')) and
             (path.endswith('js') or path.endswith('html')))
 
-  def _affects_file(filename, paths):
-    return any([filename in path for path in paths])
-
   paths = [x.LocalPath() for x in input_api.change.AffectedFiles()]
   earliest_vulcanize_change = min(os.path.getmtime(x) for x in
-                                  ['app.vulcanized.html', 'app.crisper.js'])
+                                  ['app.vulcanized.html',
+                                   'app.crisper.js',
+                                   'lazy_load.vulcanized.html',
+                                   'lazy_load.crisper.js'])
   history_changes = filter(_is_md_history_file, paths)
   latest_history_change = 0
   if history_changes:
     latest_history_change = max(os.path.getmtime(os.path.split(x)[1]) for x in
                                 history_changes)
 
   if latest_history_change > earliest_vulcanize_change:
     return [output_api.PresubmitPromptWarning(
         'Vulcanize must be run when changing files in md_history. See '
         'docs/vulcanize.md.')]
   return []