Add null check for frame when creating WebCore::Performance.

LayoutTests/fast/dom/Window/resources/window-property-collector.js

 function collectProperties()
 {
     // Collect properties of the top-level window, since touching the properties
     // of a DOMWindow affects its internal C++ state.
     collectPropertiesHelper(window, []);
 
     propertiesToVerify.sort(function (a, b)
     {
         if (a.property < b.property)
             return -1
@@ skipping 17 matching lines @@
 
     // FIXME: Skip MemoryInfo for now, since it's not implemented as a DOMWindowProperty, and has
     // no way of knowing when it's detached. Eventually this should have the same behavior.
     if (path.length >= 2 && (path[0] == 'console' || path[0] == 'performance') && path[1] == 'memory')
         return;
 
     // Skip things that are assumed to be constants.
     if (path[path.length - 1].toUpperCase() == path[path.length - 1])
         return;
 
-    // Various special cases...
+    // Various special cases for legacy reasons. Please do not add entries to this list.
     var propertyPath = path.join('.');
     switch (propertyPath) {
     case "location.href":
         expected = "'about:blank'";
         break;
     case "location.origin":
         expected = "'null'";
         break;
     case "location.pathname":
         expected = "'blank'";
         break;
     case "location.protocol":
         expected = "'about:'";
         break;
     case "navigator.appCodeName":
     case "navigator.appName":
     case "navigator.language":
     case "navigator.onLine":
     case "navigator.platform":
     case "navigator.product":
     case "navigator.productSub":
     case "navigator.vendor":
         expected = "window." + propertyPath;
         break;
-    case "navigator.battery.charging":
-        expected = "true";
-        break;
-    case "navigator.battery.chargingTime":
-        expected = "Infinity";
-        break;
-    case "navigator.battery.dischargingTime":
-        expected = "Infinity";
-        break;
-    case "navigator.battery.level":
-        expected = "1";
-        break;
     }
 
     insertExpectedResult(path, expected);
 }
 
 function collectPropertiesHelper(object, path)
 {
     if (path.length > 20)
         throw 'Error: probably looping';
 
@@ skipping 23 matching lines @@
         } else if (type == "string") {
             emitExpectedResult(path, "''");
         } else if (type == "number") {
             emitExpectedResult(path, "0");
         } else if (type == "boolean") {
             emitExpectedResult(path, "false");
         }
         path.pop();
     }
 }