Add a PRESUBMIT check for broken .ico files.

chrome/app/theme/PRESUBMIT.py

 # Copyright (c) 2012 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.
 
 """Presubmit script for Chromium theme resources.
 
 See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts
 for more details about the presubmit API built into depot_tools, and see
 http://www.chromium.org/developers/web-development-style-guide for the rules
 we're checking against here.
@@ skipping 18 matching lines @@
   # that the images modified in one are the correct scale of the other.
   path_scales = [
     [(100, 'default_100_percent/'), (200, 'default_200_percent/')],
   ]
 
   import sys
   old_path = sys.path
 
   try:
     sys.path = [resources] + old_path
-    from resource_check import resource_scale_factors
+    from resource_check import resource_scale_factors, ico_files
 
     for paths in path_scales:
       results.extend(resource_scale_factors.ResourceScaleFactors(
           input_api, output_api, paths).RunChecks())
+
+    results.extend(ico_files.IcoFiles(input_api, output_api).RunChecks())
   finally:
     sys.path = old_path
 
   return results