Add back vnu-jar for HTML validation

Gemfile

@@ -4,5 +4,5 @@ group :development, :test do
   gem 'jekyll', '~> 3.6.0'
   gem 'jekyll-redirect-from', '~> 0.12.1'
   gem 'jekyll-sitemap', '~> 1.1.1'
-  gem 'jekyll-toc', '~> 0.3.0'
+  gem 'jekyll-toc', '~> 0.4.0.rc2'
 end

Gemfile.lock

@@ -24,7 +24,7 @@ GEM
       sass (~> 3.4)
     jekyll-sitemap (1.1.1)
       jekyll (~> 3.3)
-    jekyll-toc (0.3.0)
+    jekyll-toc (0.4.0.rc2)
       nokogiri (~> 1.6)
     jekyll-watch (1.5.0)
       listen (~> 3.0, < 3.1)
@@ -61,7 +61,7 @@ DEPENDENCIES
   jekyll (~> 3.6.0)
   jekyll-redirect-from (~> 0.12.1)
   jekyll-sitemap (~> 1.1.1)
-  jekyll-toc (~> 0.3.0)
+  jekyll-toc (~> 0.4.0.rc2)
 
 BUNDLED WITH
    1.15.4

build/htmllint.js

@@ -0,0 +1,46 @@
+#!/usr/bin/env node
+
+/*!
+ * Script to run vnu-jar if Java is available.
+ * Copyright 2017 The Bootstrap Authors
+ * Copyright 2017 Twitter, Inc.
+ * Licensed under MIT (https://github.com/twbs/bootstrap/blob/master/LICENSE)
+ */
+
+'use strict'
+
+const childProcess = require('child_process')
+const vnu = require('vnu-jar')
+
+childProcess.exec('java -version', function (error) {
+  if (error) {
+    console.error('Skipping HTML lint test; Java is missing.')
+    return
+  }
+
+  const ignores = [
+    'Attribute “autocomplete” is only allowed when the input type is “color”, “date”, “datetime-local”, “email”, “hidden”, “month”, “number”, “password”, “range”, “search”, “tel”, “text”, “time”, “url”, or “week”.',
+    'Attribute “autocomplete” not allowed on element “button” at this point.',
+    'Attribute “title” not allowed on element “circle” at this point.',
+    'Bad value “tablist” for attribute “role” on element “nav”.',
+    'Element “img” is missing required attribute “src”.',
+    'Element “legend” not allowed as child of element “div” in this context.*'
+  ].join('|')
+
+  const args = [
+    '-jar',
+    vnu,
+    '--asciiquotes',
+    '--errors-only',
+    '--skip-non-html',
+    `--filterpattern "${ignores}"`,
+    '_gh_pages/',
+    'js/tests/'
+  ]
+
+  return childProcess.spawn('java', args, {
+    shell: true,
+    stdio: 'inherit'
+  })
+  .on('exit', process.exit)
+})

package.json

@@ -49,7 +49,7 @@
     "docs-compile": "bundle exec jekyll build",
     "postdocs-compile": "npm run docs-workbox-precache",
     "docs-github": "shx echo \"github: true\" > twbsconfig.yml && npm run docs-compile -- --config _config.yml,twbsconfig.yml && shx rm ./twbsconfig.yml",
-    "docs-lint": "htmllint --rc build/.htmllintrc \"_gh_pages/**/*.html\" \"js/tests/**/*.html\"",
+    "docs-lint": "htmllint --rc build/.htmllintrc \"_gh_pages/**/*.html\" \"js/tests/**/*.html\" && node build/htmllint.js",
     "docs-serve": "bundle exec jekyll serve",
     "docs-upload-preview": "build/upload-preview.sh",
     "docs-workbox-precache": "node build/workbox.js",
@@ -111,6 +111,7 @@
     "stylelint-order": "^0.7.0",
     "stylelint-scss": "^2.1.0",
     "uglify-js": "^3.0.24",
+    "vnu-jar": "^17.11.1",
     "workbox-build": "^2.0.1"
   },
   "engines": {