Print Preview: Display a throbber when the user requests the system print

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 d33f981a3798ea24a8d7cbb11cc393a67c37f591..ee6e3511dac46c3afcb96051503edd0969603b4f 100644
--- a/chrome/browser/resources/print_preview/print_preview.js
+++ b/chrome/browser/resources/print_preview/print_preview.js
@@ -48,6 +48,10 @@ var isTabHidden = false;
 // True when draft preview data is requested for preview.
 var draftDocument = true;
 
+// True if the user has click 'Advanced...' in order to open the system print
+// dialog.
+var showingSystemDialog = false;
+
 /**
  * Window onload handler, sets up the page and starts print preview by getting
  * the printer list.
@@ -169,13 +173,22 @@ function removeEventListeners() {
   $('portrait').onclick = null;
   $('printer-list').onchange = null;
 
-  // Controls that dont require preview rendering.
+  // Controls that don't require preview rendering.
   $('two-sided').onclick = null;
   $('color').onclick = null;
   $('bw').onclick = null;
 }
 
 /**
+ * Disables the input elements in the controls pane.
+ */
+function disableInputElements() {
+  var els = document.querySelectorAll('input, button, select');
+  for (var i = 0; i < els.length; i++)
+    els[i].disabled = true;
+}
+
+/**
  * Asks the browser to close the preview tab.
  */
 function handleCancelButtonClick() {
@@ -186,6 +199,9 @@ function handleCancelButtonClick() {
  * Asks the browser to show the native print dialog for printing.
  */
 function showSystemDialog() {
+  showingSystemDialog = true;
+  disableInputElements();
+  $('system-dialog-throbber').classList.remove('hidden');
   chrome.send('showSystemDialog');
 }
 
@@ -656,10 +672,6 @@ function updatePrintPreview(pageCount, jobTitle, modifiable, previewUid) {
  * @param {string} previewUid Preview unique identifier.
  */
 function createPDFPlugin(previewUid) {
-  // Enable the print button.
-  if (!$('printer-list').disabled)
-    $('print-button').disabled = false;
-
   var pdfViewer = $('pdf-viewer');
   if (pdfViewer) {
     // Need to call this before the reload(), where the plugin resets its
@@ -700,6 +712,9 @@ function checkCompatiblePluginExists() {
  * 2) The number of copies is valid (if applicable).
  */
 function updatePrintButtonState() {
+  if (showingSystemDialog)
+    return;
+
   if (getSelectedPrinterName() == PRINT_TO_PDF) {
     $('print-button').disabled = !isSelectedPagesValid();
   } else {