Fix for Hyperlinks do not open in new tab by Print preview window.

navigate function of navigator object is not getting called.

Changes done so that navigate function of navigator will get called
with proper url and newTab as true value.

BUG=453307

Review URL: https://codereview.chromium.org/886773003

Cr-Commit-Position: refs/heads/master@{#313694}

chrome/browser/resources/pdf/pdf.js

@@ -410,7 +410,7 @@ PDFViewer.prototype = {
       case 'navigate':
         // If in print preview, always open a new tab.
         if (this.isPrintPreview_)
-          this.navigate_(message.data.url, true);
+          this.navigator_.navigate(message.data.url, true);
         else
           this.navigator_.navigate(message.data.url, message.data.newTab);
         break;