Merge pull request #3263 from hypothesis/firefox-webextensions-build

Build Firefox WebExtensions during Travis builds

.jshintrc

@@ -12,7 +12,6 @@
   "esnext": true,
   "globals": {
     "chrome": false,
-    "h": false,
     "Promise": false,
     "chai": false,
     "sinon": false,
@@ -31,6 +30,7 @@
     "assert",
     "before",
     "beforeEach",
+    "chrome",
     "context",
     "describe",
     "it",

h/static/scripts/discovery.coffee

@@ -92,7 +92,11 @@ module.exports = class Discovery
     #
     #   https://developer.mozilla.org/en-US/docs/Web/API/Window/postMessage
     #
-    if origin is 'null'
+    # When sending messages to or from a Firefox WebExtension, current
+    # versions of Firefox have a bug that causes the origin check to fail even
+    # though the target and actual origins of the message match.
+    if origin is 'null' || origin.match('moz-extension:') ||
+       window.location.protocol == 'moz-extension:'
       origin = '*'
 
     # Check if the message is at all related to our discovery mechanism