Bug 1361975 Fixing tests in order to support window.location not nullable, r=me

devtools/client/framework/toolbox.js

@@ -2408,14 +2408,17 @@ Toolbox.prototype = {
         .then(() => {
           this._removeHostListeners();
 
-          // `location` may already be null if the toolbox document is already
-          // in process of destruction. Otherwise if it is still around, ensure
-          // releasing toolbox document and triggering cleanup thanks to unload
-          // event. We do that precisely here, before nullifying the target as
-          // various cleanup code depends on the target attribute to be still
+          // `location` may already be 'invalid' if the toolbox document is
+          // already in process of destruction. Otherwise if it is still
+          // around, ensure releasing toolbox document and triggering cleanup
+          // thanks to unload event. We do that precisely here, before
+          // nullifying the target as various cleanup code depends on the
+          // target attribute to be still
           // defined.
-          if (win.location) {
+          try {
             win.location.replace("about:blank");
+          } catch(e) {
+            // Do nothing;
           }
 
           // Targets need to be notified that the toolbox is being torn down.

dom/tests/mochitest/bugs/test_bug684544.html

@@ -32,7 +32,7 @@ f.remove();
 // Check that location is now null.  If it's not, the test needs changing
 // (e.g. to use window.close() so that it's null).
 is("location" in win, true, "Should still have a location property");
-is(win.location, null, "There should be no location object now");
+ok(!!win.location, "Location should not be null");
 
 // Just set the location.  This should not crash but throw an exception.
 var noException;
@@ -47,8 +47,7 @@ todo(noException, "Shouldn't throw when setting location.");
 
 // And check that we didn't override the slot in the process.
 is(typeof(win.location), "object", "Location should not have become a string");
-is(win.location, null,
-   "There should be no location object for real after the set");
+ok(!!win.location, "Location should not be null");
 
 </script>
 </pre>