[SPARK-7649] [STREAMING] [WEBUI] Use window.localStorage to store the status rather than the url

Use window.localStorage to store the status rather than the url so that the url won't be changed.

cc tdas

Author: zsxwing <zsxwing@gmail.com>

Closes #6158 from zsxwing/SPARK-7649 and squashes the following commits:

3c56fef [zsxwing] Use window.localStorage to store the status rather than the url

core/src/main/resources/org/apache/spark/ui/static/streaming-page.js

@@ -252,28 +252,16 @@ function drawHistogram(id, values, minY, maxY, unitY, batchInterval) {
 }
 
 $(function() {
-    function getParameterFromURL(param)
-    {
-        var parameters = window.location.search.substring(1); // Remove "?"
-        var keyValues = parameters.split('&');
-        for (var i = 0; i < keyValues.length; i++)
-        {
-            var paramKeyValue = keyValues[i].split('=');
-            if (paramKeyValue[0] == param)
-            {
-                return paramKeyValue[1];
-            }
-        }
-    }
-
-    var status = getParameterFromURL("show-streams-detail") == "true";
+    var status = window.localStorage && window.localStorage.getItem("show-streams-detail") == "true";
 
     $("span.expand-input-rate").click(function() {
         status = !status;
         $("#inputs-table").toggle('collapsed');
         // Toggle the class of the arrow between open and closed
         $(this).find('.expand-input-rate-arrow').toggleClass('arrow-open').toggleClass('arrow-closed');
-        window.history.pushState('', document.title, window.location.pathname + '?show-streams-detail=' + status);
+        if (window.localStorage) {
+            window.localStorage.setItem("show-streams-detail", "" + status);
+        }
     });
 
     if (status) {