Fixed JS Console Error in the Wallpaper Picker App when selecting a custom wallpaper

BUG=282303

Review URL: https://chromiumcodereview.appspot.com/23820003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@220609 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/resources/chromeos/wallpaper_manager/js/wallpaper_manager.js

@@ -615,7 +615,7 @@ function WallpaperManager(dialogDom) {
    * @private
    */
   WallpaperManager.prototype.setWallpaperAttribution_ = function(selectedItem) {
-    if (selectedItem) {
+    if (selectedItem && selectedItem.source != 'ADDNEW') {
       $('author-name').textContent = selectedItem.author;
       $('author-website').textContent = $('author-website').href =
           selectedItem.authorWebsite;