Issue 6887 - add Chrome to "npm test"

package.json

Index: package.json
diff --git a/package.json b/package.json
index fe9a51b3b85498ad037bdb07c31090a76e962dd4..f5334e8ebb39d6ea56a6aa82e879f0cbc7e1b8fc 100644
--- a/package.json
+++ b/package.json
@@ -5,9 +5,13 @@
   "dependencies": {},
   "devDependencies": {
     "//": [
-      "'dmg', 'extract-zip' and 'ncp' are needed by the module",
-      "adblockpluscore/test/download_firefox.js."
+      "'dmg', 'extract-zip' and 'ncp' are needed by `download_*.js` modules",
+      "in adblockpluscore/test/.",
+      "The chromedriver version was pinned to that exact version, due to",
+      "incompatibilities with the configured chromium version and newer",
+      "drivers."
     ],
+    "chromedriver": "2.36.0",
     "dmg": "^0.1.0",
     "eslint": "^5.1.0",
     "eslint-config-eyeo": "^2.1.0",
@@ -18,8 +22,8 @@
     "selenium-webdriver": "^3.6.0"
   },
   "scripts": {
+    "pretest": "python ensure_dependencies.py",
     "lint": "eslint *.js lib/ qunit/ ext/ test/",
-    "pretest": "python build.py devenv -t gecko",
     "test": "mocha",
     "posttest": "npm run lint"
   }