[MD Bookmarks] Add bookmark count to context menu for multiple items.

chrome/browser/resources/md_bookmarks/command_manager.html

 <link rel="import" href="chrome://resources/html/polymer.html">
 
 <link rel="import" href="chrome://resources/cr_elements/cr_action_menu/cr_action_menu.html">
 <link rel="import" href="chrome://resources/cr_elements/cr_lazy_render/cr_lazy_render.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-a11y-keys-behavior/iron-a11y-keys-behavior.html">
 <link rel="import" href="chrome://bookmarks/edit_dialog.html">
 <link rel="import" href="chrome://bookmarks/shared_style.html">
 <link rel="import" href="chrome://bookmarks/store_client.html">
 
 <dom-module id="bookmarks-command-manager">
   <template>
-    <style include="shared-style"></style>
+    <style include="shared-style">
+      .label {
+        flex: 1;
+      }
+
+      .sublabel {
+        -webkit-margin-start: 8px;
+        color: var(--secondary-text-color);
+        text-align: end;
+        width: 3ch;
+      }
+
+      :host(:not([has-any-sublabel_])) .sublabel {
+        display: none;
+      }
+    </style>
     <dialog is="cr-action-menu" id="dropdown" on-mousedown="onMenuMousedown_">
       <template is="dom-repeat" items="[[menuCommands_]]" as="command">
         <button class="dropdown-item"
             command$="[[command]]"
             hidden$="[[!isCommandVisible_(command, menuIds_)]]"
             disabled$="[[!isCommandEnabled_(command, menuIds_)]]"
             on-tap="onCommandClick_">
-          [[getCommandLabel_(command, menuIds_)]]
+          <span class="label">
+            [[getCommandLabel_(command, menuIds_)]]
+          </span>
+          <span class="sublabel">
+            [[getCommandSublabel_(command, menuIds_)]]
+          </span>
         </button>
         <hr hidden$="[[!showDividerAfter_(command, menuIds_)]]"></hr>
       </template>
     </dialog>
     <template is="cr-lazy-render" id="editDialog">
       <bookmarks-edit-dialog></bookmarks-edit-dialog>
     </template>
   </template>
   <script src="chrome://bookmarks/command_manager.js"></script>
 </dom-module>