Merge pull request #6088 from Rob--W/issue-6083

Check availability of canvas & PDF before printing

web/mozPrintCallback_polyfill.js

@@ -82,7 +82,7 @@
 
   function renderProgress() {
     var progressContainer = document.getElementById('mozPrintCallback-shim');
-    if (canvases) {
+    if (canvases && canvases.length) {
       var progress = Math.round(100 * index / canvases.length);
       var progressBar = progressContainer.querySelector('progress');
       var progressPerc = progressContainer.querySelector('.relative-progress');

web/viewer.js

@@ -1101,7 +1101,7 @@ var PDFViewerApplication = {
 
     var alertNotReady = false;
     var i, ii;
-    if (!this.pagesCount) {
+    if (!this.pdfDocument || !this.pagesCount) {
       alertNotReady = true;
     } else {
       for (i = 0, ii = this.pagesCount; i < ii; ++i) {