Print Preview: Hook up the print button to initiate a normal print operation....

chrome/browser/resources/print_preview.js

 // Copyright (c) 2010 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.
 
 var localStrings = new LocalStrings();
 var hasPDFPlugin = true;
 
 /**
  * Window onload handler, sets up the page.
  */
 function load() {
+  $('print-button').addEventListener('click', function(e) {
+    chrome.send('print');
+  });
   $('cancel-button').addEventListener('click', function(e) {
     window.close();
   });
 
   chrome.send('getPrinters');
 };
 
 /**
  * Fill the printer list drop down.
  */
@@ skipping 42 matching lines @@
   if (!pdfPlugin.onload) {
     hasPDFPlugin = false;
     mainView.removeChild(pdfPlugin);
     $('no-plugin').classList.remove('hidden');
     return;
   }
   pdfPlugin.onload('onPDFLoad()');
 }
 
 window.addEventListener('DOMContentLoaded', load);