Issue 3443 - Use process script instead of a frame script in Element Hiding Helper

lib/aardvark.js

Index: lib/aardvark.js
===================================================================
--- a/lib/aardvark.js
+++ b/lib/aardvark.js
@@ -584,48 +584,46 @@ let Aardvark = exports.Aardvark =
     this.lockedAnchor = null;
     this.boxElem = null;
     E = id => null;
     return false;
   },
 
   select: function(elem)
   {
-    if (!elem)
+    if (!elem || !this.window)
       return false;
 
-    let browser = this.browser;
-    if ("selectedBrowser" in browser)  // tabbrowser element
-      browser = browser.selectedBrowser;
-
+    let messageManager = Cc["@mozilla.org/parentprocessmessagemanager;1"]
+                           .getService(Ci.nsIMessageBroadcaster);
     let messageId = ++messageCounter;
     let callback = (message) =>
     {
       let response = message.data;
       if (response.messageId != messageId)
         return;
 
-      browser.messageManager.removeMessageListener(
+      messageManager.removeMessageListener(
         "ElemHideHelper:GetNodeInfo:Response",
         callback
       );
 
       if (!response.nodeData)
         return;
 
       this.window.openDialog("chrome://elemhidehelper/content/composer.xul",
           "_blank", "chrome,centerscreen,resizable,dialog=no", response);
       this.quit();
     };
 
-    browser.messageManager.addMessageListener(
+    messageManager.addMessageListener(
       "ElemHideHelper:GetNodeInfo:Response",
       callback
     );
-    browser.messageManager.sendAsyncMessage(
+    messageManager.broadcastAsyncMessage(
       "ElemHideHelper:GetNodeInfo",
       messageId,
       {
         element: elem
       }
     );
     return false;
   },