[adblockplus] Issue 4915 - Expose ext.i18n for background pages

ext/common.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2016 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)
 {
+  const Cu = Components.utils;
+
+  let {Services} = Cu.import("resource://gre/modules/Services.jsm", {});
+
   if (!global.ext)
     global.ext = {};
 
   var wrapperSymbol = Symbol("ext-wrapper");
 
   function wrapFrames(frames)
   {
     if (!frames.length)
       return null;
 
@@ skipping 45 matching lines @@
       this._port.on("ext_message", wrapper);
     },
 
     removeListener: function(listener)
     {
       if (listener[wrapperSymbol])
         this._port.off("ext_message", listener[wrapperSymbol]);
     }
   };
 
+  let pageName = "global";
+  if (typeof location !== "undefined")
+    pageName = location.pathname.replace(/.*\//, "").replace(/\..*?$/, "");
+
+  let stringBundle = Services.strings.createBundle(
+    "chrome://adblockplus/locale/" + pageName + ".properties?" + Math.random());
+
+  global.ext.i18n = {
+    getMessage(key, args)
+    {
+      try {
+        return stringBundle.GetStringFromName(key);
+      }
+      catch(e)
+      {
+        // Don't report errors for special strings, these are expected to be
+        // missing.
+        if (key[0] != "@")
+          Cu.reportError(e);
+        return "";
+      }
+    }
+  };
+
   if (typeof exports == "object")
     exports = global.ext;
 })(this);