[Mac] Chrome print dialog disregards system cancel key-command.

chrome/browser/resources/print_preview/print_preview.js

 // Copyright (c) 2012 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.
 
 // TODO(rltoscano): Move data/* into print_preview.data namespace
 
 var localStrings = new LocalStrings(templateData);
 
 <include src="component.js"/>
 <include src="print_preview_focus_manager.js"/>
@@ skipping 837 matching lines @@
         // instead of JS-side.
         return;
         </if>
         <if expr="not toolkit_views">
         this.close_();
         </if>
         e.preventDefault();
         return;
       }
 
+      // On Mac, Cmd- should close the print dialog.
+      if (cr.isMac && e.keyCode == 189 && e.metaKey) {
+        this.close_();
+        e.preventDefault();
+        return;
+      }
+
       // Ctrl + Shift + p / Mac equivalent.
       if (e.keyCode == 80) {
         if ((cr.isMac && e.metaKey && e.altKey && !e.shiftKey && !e.ctrlKey) ||
             (!cr.isMac && e.shiftKey && e.ctrlKey && !e.altKey && !e.metaKey)) {
           this.openSystemPrintDialog_();
           e.preventDefault();
           return;
         }
       }
 
@@ skipping 409 matching lines @@
 <include src="search/cloud_destination_list.js"/>
 <include src="search/recent_destination_list.js"/>
 <include src="search/destination_list_item.js"/>
 <include src="search/destination_search.js"/>
 <include src="search/fedex_tos.js"/>
 
 window.addEventListener('DOMContentLoaded', function() {
   printPreview = new print_preview.PrintPreview();
   printPreview.initialize();
 });