Reenable SiteEngagementBrowserTest.All for Windows.

This may have been fixed, re-enabling to gather data.

BUG=734716

Change-Id: If5400ae8e7ee202ba367d6f7fdeb71a1e4798ff7
Reviewed-on: https://chromium-review.googlesource.com/1140018Reviewed-by: Alan Cutter <alancutter@chromium.org>
Commit-Queue: calamity <calamity@chromium.org>
Cr-Commit-Position: refs/heads/master@{#575955}

chrome/test/data/webui/engagement/site_engagement_browsertest.js

@@ -46,13 +46,7 @@ SiteEngagementBrowserTest.prototype = {
   },
 };
 
-// This test is flaky on Windows. See https://crbug.com/734716.
-GEN('#if defined(OS_WIN)');
-GEN('#define MAYBE_All DISABLED_All');
-GEN('#else');
-GEN('#define MAYBE_All All');
-GEN('#endif');
-TEST_F('SiteEngagementBrowserTest', 'MAYBE_All', function() {
+TEST_F('SiteEngagementBrowserTest', 'All', function() {
   var cells;
 
   function getCells() {