Suppress some errors that are happening during teardown, when the doc…

…ument is no longer valid

addon/data/error-utils.js

@@ -4,7 +4,11 @@
 
 /** Call with an error object (with .name, .message, .help, etc) */
 function unhandled(error) {
-  console.error("Internal error", location.href);
+  try {
+    console.error("Internal error", location.href);
+  } catch (e) {
+    // Something location.href doesn't work
+  }
   self.port.emit("alertError", error);
 }
 

addon/data/selector-ui.js

@@ -416,10 +416,14 @@ const ui = (function () { // eslint-disable-line no-unused-vars
   /** Removes every UI this module creates */
   exports.remove = function () {
     for (let name in exports) {
+      if (name == "iframe") {
+        continue;
+      }
       if (typeof exports[name] == "object" && exports[name].remove) {
         exports[name].remove();
       }
     }
+    exports.iframe.remove();
   };
 
   exports.ChromeInterface = {

addon/data/shooter-interactive-worker.js

@@ -843,9 +843,14 @@ function activate() {
 
 function deactivate() {
   ui.Box.remove();
-  ui.remove();
-  removeHandlers();
-  setState("cancel");
+  try {
+    ui.remove();
+    removeHandlers();
+    setState("cancel");
+  } catch (e) {
+    // Sometimes this fires so late that the document isn't available
+    // We don't care about the exception, so we swallow it here
+  }
 }
 
 /***********************************************