Add presubmit to encourage folks to import the preconfigured polymer.html

R=dpapad@chromium.org
BUG=884428

Change-Id: Icfe2e0993204434e2639b506bd581e0fd7ef296e
Reviewed-on: https://chromium-review.googlesource.com/1227596Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Commit-Queue: Dan Beam (no longer on Chrome) <dbeam@chromium.org>
Cr-Commit-Position: refs/heads/master@{#592668}

tools/web_dev_style/html_checker.py

@@ -72,6 +72,13 @@ class HtmlChecker(object):
     return regex_check.RegexCheck(self.input_api.re, line_number, line, regex,
         "For i18n-content use javaScriptCase.")
 
+  def ImportCorrectPolymerHtml(self, line_number, line):
+    bad_import_url = r"(chrome://resources/polymer/v1_0/polymer/polymer.html)"
+    regex = self.input_api.re.compile(bad_import_url)
+    return regex_check.RegexCheck(self.input_api.re, line_number, line, regex,
+        "Please import chrome://resources/html/polymer.html instead " +
+        "(to ensure your Polymer config is set up correctly)");
+
   def LabelCheck(self, line_number, line):
     regex = self.input_api.re.compile("""
         (?:^|\s)     # start of line or whitespace
@@ -110,6 +117,7 @@ class HtmlChecker(object):
             self.DoNotUseBrElementCheck(line_number, line),
             self.DoNotUseInputTypeButtonCheck(line_number, line),
             self.I18nContentJavaScriptCaseCheck(line_number, line),
+            self.ImportCorrectPolymerHtml(line_number, line),
             self.LabelCheck(line_number, line),
             self.QuotePolymerBindings(line_number, line),
         ]))

tools/web_dev_style/html_checker_test.py

@@ -169,6 +169,24 @@ class HtmlCheckerTest(SuperMoxTestBase):
     for line in lines:
       self.ShouldPassCheck(line, self.checker.I18nContentJavaScriptCaseCheck)
 
+  def testImportCorrectPolymerHtmlFails(self):
+    bad_url = 'chrome://resources/polymer/v1_0/polymer/polymer.html'
+    lines = [
+      '<link rel="import" href="%s">' % bad_url,
+      '<link href="%s" rel="import">' % bad_url,
+    ]
+    for line in lines:
+      self.ShouldFailCheck(line, self.checker.ImportCorrectPolymerHtml)
+
+  def testImportCorrectPolymerHtmlPasses(self):
+    good_url = 'chrome://resources/html/polymer.html'
+    lines = [
+      '<link rel="import" href="%s">' % good_url,
+      '<link href="%s" rel="import">' % good_url,
+    ]
+    for line in lines:
+      self.ShouldPassCheck(line, self.checker.ImportCorrectPolymerHtml)
+
   def testLabelCheckFails(self):
     lines = [
       ' <label for="abc"',