Add user customizable launch type for apps.

chrome/browser/resources/shared/js/cr/ui/menu_item.js

Index: chrome/browser/resources/shared/js/cr/ui/menu_item.js
diff --git a/chrome/browser/resources/shared/js/cr/ui/menu_item.js b/chrome/browser/resources/shared/js/cr/ui/menu_item.js
index d570f7880977dbfc725d6c17c2cab4965e989ddc..c3e316932cc0c8a2ef4a942b057909a9ccd1a860 100644
--- a/chrome/browser/resources/shared/js/cr/ui/menu_item.js
+++ b/chrome/browser/resources/shared/js/cr/ui/menu_item.js
@@ -52,6 +52,7 @@ cr.define('cr.ui', function() {
         this.command_.removeEventListener('labelChange', this);
         this.command_.removeEventListener('disabledChange', this);
         this.command_.removeEventListener('hiddenChange', this);
+        this.command_.removeEventListener('checkedChange', this);
       }
 
       if (typeof command == 'string' && command[0] == '#') {
@@ -71,6 +72,7 @@ cr.define('cr.ui', function() {
         this.command_.addEventListener('labelChange', this);
         this.command_.addEventListener('disabledChange', this);
         this.command_.addEventListener('hiddenChange', this);
+        this.command_.addEventListener('checkedChange', this);
       }
     },
 
@@ -124,6 +126,9 @@ cr.define('cr.ui', function() {
         case 'labelChange':
           this.label = this.command.label;
           break;
+        case 'checkedChange':
+          this.checked = this.command.checked;
+          break;
       }
     }
   };
@@ -146,6 +151,12 @@ cr.define('cr.ui', function() {
    */
   cr.defineProperty(MenuItem, 'selected', cr.PropertyKind.BOOL_ATTR);
 
+  /**
+   * Whether the menu item is checked or not.
+   * @type {boolean}
+   */
+  cr.defineProperty(MenuItem, 'checked', cr.PropertyKind.BOOL_ATTR);
+
   // Export
   return {
     MenuItem: MenuItem