Prevent the default select-all behavior from happening in OOP PDF

chrome/browser/resources/pdf/pdf.js

 // Copyright 2013 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.
 
 'use strict';
 
 /**
  * @return {number} Width of a scrollbar in pixels
  */
 function getScrollbarWidth() {
@@ skipping 228 matching lines @@
         if (fromScriptingAPI) {
           position.y += Viewport.SCROLL_INCREMENT;
           this.viewport.position = position;
         }
         return;
       case 65:  // a key.
         if (e.ctrlKey || e.metaKey) {
           this.plugin_.postMessage({
             type: 'selectAll'
           });
+          // Since we do selection ourselves.
+          e.preventDefault();
         }
         return;
       case 80:  // p key.
         if (e.ctrlKey || e.metaKey) {
           this.print_();
           // Since we do the printing of the page.
           e.preventDefault();
         }
         return;
       case 219:  // left bracket.
@@ skipping 421 matching lines @@
    * Each bookmark is an Object containing a:
    * - title
    * - page (optional)
    * - array of children (themselves bookmarks)
    * @type {Array} the top-level bookmarks of the PDF.
    */
   get bookmarks() {
     return this.bookmarks_;
   }
 };