Add a PRESUBMIT check for broken .ico files.

chrome/app/theme/PRESUBMIT.py

Index: chrome/app/theme/PRESUBMIT.py
diff --git a/chrome/app/theme/PRESUBMIT.py b/chrome/app/theme/PRESUBMIT.py
index 9d0fc31a957e3124a50d11366bb06577076e9f70..5c5353f75fb5205376266163dc994eb043162440 100644
--- a/chrome/app/theme/PRESUBMIT.py
+++ b/chrome/app/theme/PRESUBMIT.py
@@ -36,11 +36,13 @@ def _CommonChecks(input_api, output_api):
 
   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