MD History: Scroll history-items into view when their action menu is opened

chrome/browser/resources/md_history/history_list.js

Index: chrome/browser/resources/md_history/history_list.js
diff --git a/chrome/browser/resources/md_history/history_list.js b/chrome/browser/resources/md_history/history_list.js
index fad3d1bd205257e43a1b4e967048a7038a92516c..f7239534b48478536ab04610b5061cd587e9753a 100644
--- a/chrome/browser/resources/md_history/history_list.js
+++ b/chrome/browser/resources/md_history/history_list.js
@@ -29,6 +29,7 @@ Polymer({
 
   listeners: {
     'remove-bookmark-stars': 'removeBookmarkStars_',
+    'open-menu': 'onOpenMenu_',
   },
 
   /** @override */
@@ -105,6 +106,19 @@ Polymer({
   },
 
   /**
+   * Ensure that the item is visible in the scroll pane when its menu is
+   * opened (it is possible to open off-screen items using keyboard shortcuts).
+   * @param {Event} e
+   * @private
+   */
+  onOpenMenu_: function(e) {
+    var index = e.detail.index;
+    var list = /** @type {IronListElement} */ (this.$['infinite-list']);
+    if (index < list.firstVisibleIndex || index > list.lastVisibleIndex)
+      list.scrollToIndex(index);
+  },
+
+  /**
    * Check whether the time difference between the given history item and the
    * next one is large enough for a spacer to be required.
    * @param {HistoryEntry} item