Add shortcuts for zoom, print and saving PDFs.

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.
 
 (function() {
 
 <include src="../../../../ui/webui/resources/js/util.js"></include>
 <include src="viewport.js"></include>
 
 // The plugin element is sized to fill the entire window and is set to be fixed
@@ skipping 113 matching lines @@
       viewport.fitToWidth.bind(viewport));
   $('fit-to-page-button').addEventListener('click',
       viewport.fitToPage.bind(viewport));
   $('zoom-in-button').addEventListener('click',
       viewport.zoomIn.bind(viewport));
   $('zoom-out-button').addEventListener('click',
       viewport.zoomOut.bind(viewport));
   $('save-button-link').href = streamDetails.originalURL;
   $('print-button').addEventListener('click', print);
 
-
   // Setup keyboard event listeners.
   document.onkeydown = function(e) {
     switch (e.keyCode) {
       case 37:  // Left arrow key.
         // Go to the previous page if there are no horizontal scrollbars.
         if (!viewport.documentHasScrollbars().x) {
           viewport.goToPage(viewport.getMostVisiblePage() - 1);
           // Since we do the movement of the page
           e.preventDefault();
         }
@@ skipping 12 matching lines @@
           e.preventDefault();
         }
         return;
       case 34:  // Page down key.
         // Go to the next page if we are fit-to-page.
         if (isFitToPageEnabled()) {
           viewport.goToPage(viewport.getMostVisiblePage() + 1);
           e.preventDefault();
         }
         return;
+      case 187:  // +/= key.
+      case 107:  // Numpad + key.
+        if (e.ctrlKey)
+          viewport.zoomIn();
+        return;
+      case 189:  // -/_ key.
+      case 109:  // Numpad - key.
+        if (e.ctrlKey)
+          viewport.zoomOut();
+        return;
+      case 83:  // s key.
+        if (e.ctrlKey) {
+          // Simulate a click on the button so that the <a download ...>
+          // attribute is used.
+          $('save-button-link').click();
+        }
+        return;
+      case 80:  // p key.
+        if (e.ctrlKey) {
+          print();
+          e.preventDefault();
+        }
+        return;
     }
   };
 }
 
 load();
 
 })();