Issue 1663 - Emulate background page and implement proper message responder

ext/background.js

Index: ext/background.js
===================================================================
new file mode 100644
--- /dev/null
+++ b/ext/background.js
@@ -0,0 +1,49 @@
+/*
+ * This file is part of Adblock Plus <http://adblockplus.org/>,
+ * Copyright (C) 2006-2014 Eyeo GmbH
+ *
+ * Adblock Plus is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 3 as
+ * published by the Free Software Foundation.
+ *
+ * Adblock Plus is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+(function(global)
+{
+  if (!global.ext)
+    global.ext = {};
+
+  window.addEventListener("load", function()
+  {
+    parent.postMessage({
+      type: "backgroundPageLoaded"
+    }, "*");
+  }, false)
+
+  var removalListeners = [];
+  ext.onPageRemoved = {
+    addListener: function(listener)
+    {
+      if (removalListeners.indexOf(listener) < 0)
+        removalListeners.push(listener)
+    }
+  };
+
+  parent.addEventListener("unload", function()
+  {
+    var comparator = function(page)
+    {
+      return page._source == parent;
+    };
+
+    for (var i = 0; i < removalListeners.length; i++)
+      removalListeners[i](comparator);
+  }, false);
+})(this);