MD WebUI: Strip comments from vulcanized JS files

chrome/browser/resources/vulcanize.py

Index: chrome/browser/resources/vulcanize.py
diff --git a/chrome/browser/resources/vulcanize.py b/chrome/browser/resources/vulcanize.py
index d2773161da0bc23add7d1747bd3eca15184fc6ff..1d5aa17309d23c111d4813dab1399ed69772d437 100755
--- a/chrome/browser/resources/vulcanize.py
+++ b/chrome/browser/resources/vulcanize.py
@@ -4,6 +4,7 @@
 # found in the LICENSE file.
 
 import os
+import re
 import subprocess
 import sys
 import tempfile
@@ -49,6 +50,31 @@ _VULCANIZE_BASE_ARGS = [
 ]
 
 
+def _strip_js_comments(filename):
+  start_comment = re.compile(r'^ */\*\*?$')
+  end_comment = re.compile(r'^ *\*\*?/$')
+  single_line_comment = re.compile(r'^ *//')
+  keep_comment = re.compile(r'Copyright|license|LICENSE|\<\/?if')

[michaelpg, 2016/08/17 07:39:56]

ugh, grit works inside comments? what about
    // <include

[tsergeant, 2016/08/17 07:57:52]

The commented-if is used in one place in util.js. You can check with dbeam for
why it is commented out.

Includes have already been explicitly disabled by this stage so they don't need
to be handled here.

+
+  with open(filename) as f:
+    contents = f.readlines()
+
+  out_lines = []
+  inside_comment = False
+
+  for line in contents:
+    if not inside_comment:
+      if start_comment.match(line):
+        inside_comment = True
+      elif not single_line_comment.match(line) or keep_comment.search(line):
+        out_lines.append(line)
+    elif end_comment.match(line):
+      inside_comment = False
+
+  with open(filename, 'w') as f:
+    f.writelines(out_lines)
+
+
 def _vulcanize(directory, host, html_in_file, html_out_file='vulcanized.html',
                js_out_file='crisper.js', extra_args=None):
   def _run_cmd(cmd_parts, stdout=None):
@@ -85,6 +111,8 @@ def _vulcanize(directory, host, html_in_file, html_out_file='vulcanized.html',
                          '--script-in-head', 'false',
                          '--html', html_out_path,
                          '--js', js_out_path])
+
+    _strip_js_comments(js_out_path)
   finally:
     os.remove(tmp.name)