[MD Bookmarks] Deselect items when clicking outside the bookmark card.

chrome/browser/resources/md_bookmarks/reducers.js

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /**
  * @fileoverview Module of functions which produce a new page state in response
  * to an action. Reducers (in the same sense as Array.prototype.reduce) must be
  * pure functions: they must not modify existing state objects, or make any API
  * calls.
  */
@@ skipping 35 matching lines @@
   /**
    * @param {SelectionState} selection
    * @param {Action} action
    * @return {SelectionState}
    */
   SelectionState.updateSelection = function(selection, action) {
     switch (action.name) {
       case 'clear-search':
       case 'finish-search':
       case 'select-folder':
+      case 'deselect-items':
         return SelectionState.deselectAll(selection);
       case 'select-items':
         return SelectionState.selectItems(selection, action);
     }
     return selection;
   };
 
   var SearchState = {};
 
   /**
@@ skipping 278 matching lines @@
 
   return {
     reduceAction: reduceAction,
     ClosedFolderState: ClosedFolderState,
     NodeState: NodeState,
     SearchState: SearchState,
     SelectedFolderState: SelectedFolderState,
     SelectionState: SelectionState,
   };
 });