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

chrome/browser/printing/print_preview_tab_controller.cc

Index: chrome/browser/printing/print_preview_tab_controller.cc
diff --git a/chrome/browser/printing/print_preview_tab_controller.cc b/chrome/browser/printing/print_preview_tab_controller.cc
index 0d94be172f689e541f0bf6fe1d5f13e7c51cd1d1..78d7fab2667d2d4092ac1dcc286c5c1790e553b1 100644
--- a/chrome/browser/printing/print_preview_tab_controller.cc
+++ b/chrome/browser/printing/print_preview_tab_controller.cc
@@ -138,6 +138,16 @@ void PrintPreviewTabController::Observe(NotificationType type,
     if (initiator_tab)
       RemoveObservers(initiator_tab);
 
+    // |source_tab_is_preview_tab| is misleading in the case where the user
+    // chooses to re-open the initiator tab after closing it, as |source_tab|
+    // has navigated to the URL of the initiator tab at this point. Make sure to
+    // verify that |source_tab| really is a print preview tab.
+    if (IsPrintPreviewTab(source_tab)) {
+      PrintPreviewUI* print_preview_ui =
+          static_cast<PrintPreviewUI*>(source_tab->web_ui());
+      print_preview_ui->OnNavigation();
+    }
+
     // Erase the map entry.
     preview_tab_map_.erase(source_tab);
   } else {