Since UNDEFINED in JS is mapped to null by the Gwt glue glue code, this patch
makes CheckBox.java more robust against user/browser code that returns
UNDEFINED for getAccessKey.

Accidentally bumped into this while trying to debug a failure with HtmlUnit,
which currently returns UNDEFINED for getAccessKey. 

Patch by: rjrjr, amitmanjhi (pair programming)
Review by: amitmanjhi, rjrjr


git-svn-id: https://google-web-toolkit.googlecode.com/svn/branches/farewellSwt@6152 8db76d5a-ed1c-0410-87a9-c151d255dfc7
diff --git a/user/src/com/google/gwt/user/client/ui/CheckBox.java b/user/src/com/google/gwt/user/client/ui/CheckBox.java
index 92419cd..6726b67 100644
--- a/user/src/com/google/gwt/user/client/ui/CheckBox.java
+++ b/user/src/com/google/gwt/user/client/ui/CheckBox.java
@@ -399,7 +399,7 @@
     // Setup the new element
     Event.sinkEvents(inputElem, sunkEvents);
     inputElem.setId(uid);
-    if (!accessKey.equals("")) {
+    if (!"".equals(accessKey)) {
       inputElem.setAccessKey(accessKey);
     }
     setTabIndex(tabIndex);