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

ext/common.js

Index: ext/common.js
diff --git a/ext/common.js b/ext/common.js
index c00cfffac710285aeef7b16823cd952067c7ea4c..ae0a12ca9a466bcd1424d37759ca6181a920264f 100644
--- a/ext/common.js
+++ b/ext/common.js
@@ -17,6 +17,10 @@
 
 (function(global)
 {
+  const Cu = Components.utils;
+
+  let {Services} = Cu.import("resource://gre/modules/Services.jsm", {});
+
   if (!global.ext)
     global.ext = {};
 
@@ -82,6 +86,30 @@
     }
   };
 
+  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);