[Presubmit] check for single quotes in html properties

chrome/browser/web_dev_style/html_checker.py

Index: chrome/browser/web_dev_style/html_checker.py
diff --git a/chrome/browser/web_dev_style/html_checker.py b/chrome/browser/web_dev_style/html_checker.py
index 422b7852185410a6f833185faee07bc96a269034..bca4f2f5bd2e07fdd7e487df48dbeaec62ca9fc1 100644
--- a/chrome/browser/web_dev_style/html_checker.py
+++ b/chrome/browser/web_dev_style/html_checker.py
@@ -44,6 +44,17 @@ class HtmlChecker(object):
     return regex_check.RegexCheck(self.input_api.re, line_number, line, regex,
         'Use the button element instead of <input type="button">')
 
+  def DoNotUseSingleQuotesCheck(self, line_number, line):
+    regex = self.input_api.re.compile("""
+        (<\S+                          # The tag name.
+        (?:\s+\S+\$?="[^"]*"|\s+\S+)*  # Correctly quoted or non-value props.
+        \s+\S+\$?='[^']*'              # Find incorrectly quoted (foo='bar').
+        [^>]*>)                        # To the end of the tag.

[Dan Beam, 2016/06/25 00:49:03]

why is the match around the whole tag?  why not just around the single quotes or
singly-quoted part?

[dschuyler, 2016/06/28 19:04:18]

I'd thought that the context around the error would be helpful.
Though I can also see it being helpful to narrow down error to
better see what the issue is. It now has the property name and
value.

Done.

+        """,
+        self.input_api.re.MULTILINE | self.input_api.re.VERBOSE)
+    return regex_check.RegexCheck(self.input_api.re, line_number, line, regex,
+        'Use double quotes rather than single quotes in HTML properties')
+
   def I18nContentJavaScriptCaseCheck(self, line_number, line):
     regex = self.input_api.re.compile("""
         (?:^|\s)                      # start of line or whitespace