[MD History] Implement grouped history UI.

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

Index: chrome/test/data/webui/md_history/test_util.js
diff --git a/chrome/test/data/webui/md_history/test_util.js b/chrome/test/data/webui/md_history/test_util.js
index d0a3fc433140dc1161ffcea40af71e00f5ffab85..c49200d75ddaff05026526c62a9338a88866f9e1 100644
--- a/chrome/test/data/webui/md_history/test_util.js
+++ b/chrome/test/data/webui/md_history/test_util.js
@@ -55,3 +55,19 @@ function createSearchEntry(timestamp, urlStr) {
 
   return entry;
 }
+
+/**
+ * Create a simple HistoryInfo.
+ * @param {?string} searchTerm The search term that the info has. Will be empty
+ *     string if not specified.
+ * @return {!HistoryInfo}
+ */
+function createHistoryInfo(searchTerm) {
+  return {
+          finished: true,

[tsergeant, 2016/05/25 05:06:56]

Nit: normal formatting is probably

return {
  finished: true
  ...
};

[calamity, 2016/05/25 05:51:41]

Done.

+          hasSyncedResults: false,
+          queryEndTime: 'Monday',
+          queryStartTime: 'Tuesday',
+          term: searchTerm || ''
+        };
+}