Update from https://crrev.com/333737

mojo/tools/roll/update_from_chromium.py

 #!/usr/bin/env python
 # Copyright 2014 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 argparse
 import json
 import os
 import subprocess
 import sys
@@ skipping 39 matching lines @@
     "third_party/cython",
 ]
 
 # These directories are snapshotted from chromium without modifications.
 dirs_to_snapshot = base_deps + build_deps + sandbox_deps + mojo_sdk_deps
 
 files_to_copy = [ "sandbox/sandbox_export.h" ]
 
 # The contents of these files before the roll will be preserved after the roll,
 # even though they live in directories rolled in from Chromium.
-files_not_to_roll = [ "build/module_args/mojo.gni" ]
+files_not_to_roll = [
+    "build/config/ui.gni",
+    "build/ls.py",
+    "build/module_args/mojo.gni",
+]
 
 dirs = dirs_to_snapshot
 
 def chromium_rev_number(src_commit):
   base_url = "https://cr-rev.appspot.com/_ah/api/crrev/v1/commit/"
   commit_info = json.load(urllib2.urlopen(base_url + src_commit))
   return commit_info["numberings"][0]["number"]
 
 def rev(source_dir):
   for d in dirs:
@@ skipping 37 matching lines @@
 
   print "Restoring files whose contents don't track Chromium"
   for f in files_not_to_roll:
     system(["git", "checkout", pre_roll_commit, "--", f], cwd=mojo_root_dir)
   if files_not_to_roll:
     commit("Restored pre-roll versions of files that don't get rolled")
   return 0
 
 if __name__ == "__main__":
   sys.exit(main())