Better handling of broken applet codebase

Source/core/html/HTMLAppletElement.cpp

Index: Source/core/html/HTMLAppletElement.cpp
diff --git a/Source/core/html/HTMLAppletElement.cpp b/Source/core/html/HTMLAppletElement.cpp
index 91b3cbb7d897d02c00ae4df2189ac6e4fe06c921..b62750492630ba84a99d18c31341ef6932ddaac0 100644
--- a/Source/core/html/HTMLAppletElement.cpp
+++ b/Source/core/html/HTMLAppletElement.cpp
@@ -151,7 +151,12 @@ void HTMLAppletElement::updateWidgetInternal()
     // attribute is set, then 'code' points to a class inside the archive, so we need to check the
     // url generated by resolving 'archive' against 'codebase'.
     KURL urlToCheck;
-    KURL rootURL = codeBase.isNull() ? document().url() : document().completeURL(codeBase);
+    KURL rootURL;
+    if (!codeBase.isNull())
+        rootURL = document().completeURL(codeBase);
+    if (rootURL.isNull() || !rootURL.isValid())
+        rootURL = document().url();
+
     if (!archive.isNull())
         urlToCheck = KURL(rootURL, archive);
     else if (!code.isNull())