Disable MaterialHistoryBrowserTest.HistoryListTest since

chrome/test/data/webui/md_history/md_history_browsertest.js

Index: chrome/test/data/webui/md_history/md_history_browsertest.js
diff --git a/chrome/test/data/webui/md_history/md_history_browsertest.js b/chrome/test/data/webui/md_history/md_history_browsertest.js
index 61777b5c0695f11a8334f024f6d30224209b204c..c7bf5f3dcd1cbffc33e38215ca0d90326e63ab62 100644
--- a/chrome/test/data/webui/md_history/md_history_browsertest.js
+++ b/chrome/test/data/webui/md_history/md_history_browsertest.js
@@ -86,7 +86,8 @@ TEST_F('MaterialHistoryBrowserTest', 'HistoryItemTest', function() {
   mocha.run();
 });
 
-TEST_F('MaterialHistoryBrowserTest', 'HistoryListTest', function() {
+// Flaky on chromeos, http://crbug.com/640862
+TEST_F('MaterialHistoryBrowserTest', 'DISABLED_HistoryListTest', function() {
   md_history.history_list_test.registerTests();
   mocha.run();
 });