web_dev_style: ignore --css-vars from alphabetical ordering requirement

chrome/browser/web_dev_style/css_checker.py

Index: chrome/browser/web_dev_style/css_checker.py
diff --git a/chrome/browser/web_dev_style/css_checker.py b/chrome/browser/web_dev_style/css_checker.py
index 77f610f4db804a7f0c0e52f8400ad54333d9de5d..d55bcca6be62b95d7aeb1195b3dc02c3f4f2a056 100644
--- a/chrome/browser/web_dev_style/css_checker.py
+++ b/chrome/browser/web_dev_style/css_checker.py
@@ -29,42 +29,42 @@ class CSSChecker(object):
       return s[0] == s[1] == s[2] if len(s) == 3 else s[0:2] == s[2:4] == s[4:6]
 
     def _remove_all(s):
-      s = _remove_grit(s)
+      s = _remove_grit(s)  # Must be done first.
       s = _remove_ats(s)
       s = _remove_comments(s)
+      s = _remove_mixins_and_valid_vars(s)
       s = _remove_template_expressions(s)
-      s = _remove_mixins(s)
       return s
 
     def _extract_inline_style(s):
       return '\n'.join(re.findall(r'<style\b[^>]*>([^<]*)<\/style>', s))
 
     def _remove_ats(s):
-      at_reg = re.compile(r"""
+      return re.sub(r"""
           @(?!apply)(?!\d+x\b)    # @at-keyword, not (apply|2x)
           \w+[^'"]*?{             # selector junk {
           (.*{.*?})+              # inner { curly } blocks, rules, and selector
           .*?}                    # stuff up to the first end curly }
-          """,
-          re.DOTALL | re.VERBOSE)
-      return at_reg.sub('\\1', s)
+          """, r'\1', s, flags=re.DOTALL | re.VERBOSE)
 
     def _remove_comments(s):
-      return re.sub(re.compile(r'/\*.*?\*/', re.DOTALL), '', s)
-
-    def _remove_mixins(s):
-      return re.sub(re.compile(r'--[\d\w-]+: {.*?};', re.DOTALL), '', s)
-
-    def _remove_template_expressions(s):
-      return re.sub(re.compile(r'\$i18n(Raw)?{[^}]*}', re.DOTALL), '', s)
+      return re.sub(r'/\*.*?\*/', '', s, flags=re.DOTALL)
 
     def _remove_grit(s):
-      grit_reg = re.compile(r"""
+      return re.sub(r"""
           <if[^>]+>.*?<\s*/\s*if[^>]*>|  # <if> contents </if>
           <include[^>]+>                 # <include>
-          """,
-          re.DOTALL | re.VERBOSE)
-      return re.sub(grit_reg, '', s)
+          """, '', s, flags=re.DOTALL | re.VERBOSE)
+
+    mixin_shim_reg = r'[\w-]+_-_[\w-]+'
+
+    def _remove_mixins_and_valid_vars(s):
+      valid_vars = r'--(?!' + mixin_shim_reg + r')[\w-]+:\s*'
+      mixin_or_value = r'({.*?}|[^;}]+);?\s*'
+      return re.sub(valid_vars + mixin_or_value, '', s, flags=re.DOTALL)
+
+    def _remove_template_expressions(s):
+      return re.sub(r'\$i18n(Raw)?{[^}]*}', '', s, flags=re.DOTALL)
 
     def _rgb_from_hex(s):
       if len(s) == 3:
@@ -170,7 +170,7 @@ class CSSChecker(object):
       return re.search(r'\(\s*\s*data:', line)
 
     def no_mixin_shims(line):
-      return re.search('\-\-[\w\-]+_\-_[\w\-]+\s*:', line)
+      return re.search(r'--' + mixin_shim_reg + r'\s*:', line)
 
     def no_quotes_in_url(line):
       return re.search('url\s*\(\s*["\']', line, re.IGNORECASE)