WebUI: Swap Uglify with Closure Compiler NodeJS version.

chrome/browser/resources/vulcanize_gn.py

 #!/usr/bin/env python
 # 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 argparse
 import itertools
 import os
 import platform
 import re
@@ skipping 154 matching lines @@
     node.RunNode([node_modules.PathToCrisper(),
                  '--source', tmp.name,
                  '--script-in-head', 'false',
                  '--html', html_out_path,
                  '--js', js_out_path])
 
     # Create an empty JS file if crisper did not create one.
     if not os.path.isfile(js_out_path):
       open(js_out_path, 'w').close()
 
-    node.RunNode([node_modules.PathToUglifyJs(), js_out_path,
-                  '--comments', '"/Copyright|license|LICENSE|\<\/?if/"',
-                  '--output', js_out_path])
+    # Rewrite licenses such that Closure Compiler will preserve them.
+    import rewrite_licenses
+    with open(js_out_path, 'r') as f:
+      output_data = rewrite_licenses.rewrite(f.read())
+
+    # Open file again with 'w' such that the previous contents are overwritten.
+    with open(js_out_path, 'w') as f:
+      f.write(output_data)
+      f.close()
+
+    output = node.RunNode([node_modules.PathToClosureCompiler(), js_out_path])
+    with open(js_out_path, 'w') as output_file:
+      output_file.write(output)
+
   finally:
     os.remove(tmp.name)
 
 
 def main(argv):
   parser = argparse.ArgumentParser()
   parser.add_argument('--depfile', required=True)
   parser.add_argument('--exclude', nargs='*')
   parser.add_argument('--host', required=True)
   parser.add_argument('--html_in_file', required=True)
@@ skipping 10 matching lines @@
   args.depfile = os.path.normpath(args.depfile)
   args.input = os.path.normpath(args.input)
   args.out_folder = os.path.normpath(args.out_folder)
 
   _vulcanize(args.input, args)
   _update_dep_file(args.input, args)
 
 
 if __name__ == '__main__':
   main(sys.argv[1:])