Guard against menu onclick being called twice

 Bug: 4375496

Change-Id: Id1523ce179bcd4a5f66065109e3dd97d0a8f9ff4
diff --git a/src/com/android/browser/WallpaperHandler.java b/src/com/android/browser/WallpaperHandler.java
index 2cb223a..cd896da 100644
--- a/src/com/android/browser/WallpaperHandler.java
+++ b/src/com/android/browser/WallpaperHandler.java
@@ -68,7 +68,7 @@
 
     @Override
     public boolean onMenuItemClick(MenuItem item) {
-        if (mUrl != null) {
+        if (mUrl != null && getState() == State.NEW) {
             // The user may have tried to set a image with a large file size as
             // their background so it may take a few moments to perform the
             // operation.