Print preview not showing if default print is invalid.

chrome/browser/printing/print_preview_message_handler.cc

 // Copyright (c) 2011 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.
 
 #include "chrome/browser/printing/print_preview_message_handler.h"
 
 #include <vector>
 
 #include "base/memory/ref_counted.h"
 #include "base/memory/ref_counted_memory.h"
@@ skipping 193 matching lines @@
   PrintPreviewUI* print_preview_ui =
       static_cast<PrintPreviewUI*>(print_preview_tab->web_ui());
   print_preview_ui->OnDidGetDefaultPageLayout(page_layout_in_points);
 }
 
 void PrintPreviewMessageHandler::OnPrintPreviewCancelled(int document_cookie) {
   // Always need to stop the worker.
   StopWorker(document_cookie);
 }
 
+void PrintPreviewMessageHandler::OnInvalidPrinterSettings(int document_cookie) {
+  // Always need to stop the worker.
+  StopWorker(document_cookie);

[kmadhusu, 2011/08/30 02:11:27]

You need to stop the worker only if the document_cookie is valid.

[arthurhsu, 2011/08/30 20:43:03]

Done.

+
+  TabContents* print_preview_tab = GetPrintPreviewTab();
+  if (!print_preview_tab)
+    return;
+
+  bool show_as_alert = false;
+  TabContentsWrapper* wrapper =
+      TabContentsWrapper::GetCurrentWrapperForContents(print_preview_tab);
+  if (g_browser_process->background_printing_manager()->
+          HasTabContents(wrapper)) {
+    // Preview tab was hidden to serve the print request.
+    show_as_alert = true;
+  }
+
+  PrintPreviewUI* print_preview_ui =
+      static_cast<PrintPreviewUI*>(print_preview_tab->web_ui());
+  print_preview_ui->OnInvalidPrinterSettings(show_as_alert);

[kmadhusu, 2011/08/30 02:11:27]

If you are going to display the alert from javascript, you can easily identify
whether the tab is hidden or not in print_preview.js using |isTabHidden|
variable. Therefore, you can remove |show_as_alert| param here and hence lines
222-229 is not required here.


Having said that, we still want to delete the background printing tab (which is
the hidden preview tab) after the alert is shown and the user has clicked "Ok"
button. You may want to listen for the user action and then send a message from
javascript to c++ to close/delete the hidden preview tab wrapper. 

[arthurhsu, 2011/08/30 20:43:03]

Per discussion, changed to follow the OnPrintPreviewFailed pattern.

+}
+
 bool PrintPreviewMessageHandler::OnMessageReceived(
     const IPC::Message& message) {
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP(PrintPreviewMessageHandler, message)
     IPC_MESSAGE_HANDLER(PrintHostMsg_RequestPrintPreview,
                         OnRequestPrintPreview)
     IPC_MESSAGE_HANDLER(PrintHostMsg_DidGetPreviewPageCount,
                         OnDidGetPreviewPageCount)
     IPC_MESSAGE_HANDLER(PrintHostMsg_DidPreviewPage,
                         OnDidPreviewPage)
     IPC_MESSAGE_HANDLER(PrintHostMsg_PagesReadyForPreview,
                         OnPagesReadyForPreview)
     IPC_MESSAGE_HANDLER(PrintHostMsg_PrintPreviewFailed,
                         OnPrintPreviewFailed)
     IPC_MESSAGE_HANDLER(PrintHostMsg_DidGetDefaultPageLayout,
                         OnDidGetDefaultPageLayout)
     IPC_MESSAGE_HANDLER(PrintHostMsg_PrintPreviewCancelled,
                         OnPrintPreviewCancelled)
+    IPC_MESSAGE_HANDLER(PrintHostMsg_PrintPreviewInvalidPrinterSettings,
+                        OnInvalidPrinterSettings)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
   return handled;
 }
 
 void PrintPreviewMessageHandler::DidStartLoading() {
   if (tab_contents()->delegate() &&
       printing::PrintPreviewTabController::IsPrintPreviewTab(tab_contents())) {
     tab_contents()->SetContentRestrictions(CONTENT_RESTRICTION_PRINT);
   }
 }
 
 }  // namespace printing