152387 - prefs for location bar autocomplete don't stick. r=caillon sr=ben

xpfe/global/resources/content/nsWidgetStateManager.js

@@ -87,6 +87,8 @@ function nsWidgetStateManager ( aFrameID )
           {  get: wsm.get_Textbox,     set: wsm.set_Textbox       },
         listitem:
           {  get: wsm.get_Listitem,    set: wsm.set_Listitem      },
+        data:
+          {  get: wsm.get_Data,        set: wsm.set_Data          },
         default_handler:
           {  get: wsm.get_Default,     set: wsm.set_Default       }
       }
@@ -198,7 +200,7 @@ nsWidgetStateManager.prototype =
                 {
                   if (property == "localname")
                     continue;
-                  if ( !aDataObject[property] )
+                  if ( !aDataObject[property] && typeof aDataObject[property] == "boolean")
                     aElement.removeAttribute( property );
                   else
                     aElement.setAttribute( property, aDataObject[property] );
@@ -365,6 +367,32 @@ nsWidgetStateManager.prototype =
           return null;
         },
 
+    // <data>
+    set_Data:
+      function ( aElementID, aDataObject )
+        {
+
+          var element = wsm.contentArea.document.getElementById( aElementID );
+          wsm.generic_Set( element, aDataObject );
+          if( 'value' in aDataObject )
+            {
+              element.setAttribute("value", aDataObject.value);
+            }
+        },
+
+    get_Data:
+      function ( aElementID )
+        {
+          var element = wsm.contentArea.document.getElementById( aElementID );
+          var dataObject = wsm.generic_Get( element );
+          if( dataObject )
+            {
+              dataObject.value = element.getAttribute( "value" );
+              return dataObject;
+            }
+          return null;
+        },
+
     // <default>
     set_Default:
       function ( aElementID, aDataObject )