inject (again) chrome-browser-polyfill.js (see #782)

manifest.json

@@ -30,6 +30,7 @@
 			],
 			"run_at": "document_start",
 			"js": [
+				"dist/chrome-browser-polyfill.js",
 				"dist/single-file-bootstrap.js",
 				"dist/extension-bootstrap.js",
 				"dist/web/infobar-web.js"