Implement PrintBrowser functionality.

chrome/browser/resources/print_preview/print_preview.js

Index: chrome/browser/resources/print_preview/print_preview.js
diff --git a/chrome/browser/resources/print_preview/print_preview.js b/chrome/browser/resources/print_preview/print_preview.js
index 0c5f7c9cda4444f6bdd7a5b8a1ae175e20753428..12b450b94496d9671247a78b4e26e369a81db3d2 100644
--- a/chrome/browser/resources/print_preview/print_preview.js
+++ b/chrome/browser/resources/print_preview/print_preview.js
@@ -19,6 +19,12 @@ cr.define('print_preview', function() {
     print_preview.Component.call(this);
 
     /**
+     * If in PrintBrowser mode, don't show the navbar
+     */
+    if (loadTimeData.getBoolean('printBrowserEnabled'))
+      $('navbar-container').style.display = 'none';

[rbpotter, 2016/12/16 20:05:29]

Not sure that this stops all the events from the navbar. If you open print
preview, apply this styling, then hit "enter" you can still print the page,
which seems unexpected.

+
+    /**
      * Whether the print scaling feature is enabled.
      * @type {boolean}
      * @private