MD History: Add shortcuts for 'Delete' and 'Backspace' to delete selected items

chrome/browser/resources/md_history/app.js

Index: chrome/browser/resources/md_history/app.js
diff --git a/chrome/browser/resources/md_history/app.js b/chrome/browser/resources/md_history/app.js
index 6761359aa0b888dfd54cd345bcc9c6e70c9b3dd3..efd6820660c243bbdf4055ef8e9ac2b6b17e40d0 100644
--- a/chrome/browser/resources/md_history/app.js
+++ b/chrome/browser/resources/md_history/app.js
@@ -135,6 +135,9 @@ Polymer({
             !(this.$.toolbar.searchBar.showingSearch &&
               this.$.toolbar.searchBar.isSearchFocused());
         break;
+      case 'delete-command':
+        e.canExecute = this.$.toolbar.count > 0;
+        break;
     }
   },
 
@@ -145,6 +148,8 @@ Polymer({
   onCommand_: function(e) {
     if (e.command.id == 'find-command' || e.command.id == 'slash-command')
       this.$.toolbar.showSearchField();
+    if (e.command.id == 'delete-command')
+      this.deleteSelected();
   },
 
   /**