[MD History] Make sidebar menu respond to spacebar.

chrome/browser/resources/md_history/side_bar.js

Index: chrome/browser/resources/md_history/side_bar.js
diff --git a/chrome/browser/resources/md_history/side_bar.js b/chrome/browser/resources/md_history/side_bar.js
index a652263760e398ec0482673df52f6596cd4f1e01..af89170d3640543299989611ddf2e6a4607bb4cd 100644
--- a/chrome/browser/resources/md_history/side_bar.js
+++ b/chrome/browser/resources/md_history/side_bar.js
@@ -5,6 +5,8 @@
 Polymer({
   is: 'history-side-bar',
 
+  behaviors: [Polymer.IronA11yKeysBehavior],
+
   properties: {
     selectedPage: {type: String, notify: true},
 
@@ -16,6 +18,18 @@ Polymer({
     drawer: {type: Boolean, reflectToAttribute: true},
   },
 
+  keyBindings: {
+    'space:keydown': 'onSpacePressed_',
+  },
+
+  /**
+   * @param {CustomEvent} e
+   * @private
+   */
+  onSpacePressed_: function(e) {
+    e.detail.keyboardEvent.path[0].click();
+  },
+
   /**
    * @private
    */