MD History: Trim long item titles to reduce effect on performance

chrome/browser/resources/md_history/history_item.js

Index: chrome/browser/resources/md_history/history_item.js
diff --git a/chrome/browser/resources/md_history/history_item.js b/chrome/browser/resources/md_history/history_item.js
index 78aa976b52b71fca43e68ef52f297bfdc70e63e1..2497a6f525fd7c79a08d6ceae3de6d0a1055d335 100644
--- a/chrome/browser/resources/md_history/history_item.js
+++ b/chrome/browser/resources/md_history/history_item.js
@@ -81,6 +81,18 @@ cr.define('md_history', function() {
       var resultId = numberOfItems == 1 ? 'searchResult' : 'searchResults';
       return loadTimeData.getStringF('foundSearchResults', numberOfItems,
           loadTimeData.getString(resultId), search);
+    },
+
+    /**
+     * Crop long item titles to reduce their effect on layout performance. See
+     * crbug.com/621347.
+     * @param {string} title
+     * @return {string}
+     */
+    cropItemTitle_: function(title) {
+      return (title.length > TITLE_MAX_LENGTH) ?
+          title.substr(0, TITLE_MAX_LENGTH) :
+          title;
     }
   });