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

chrome/browser/ui/webui/print_preview_ui.cc

Index: chrome/browser/ui/webui/print_preview_ui.cc
diff --git a/chrome/browser/ui/webui/print_preview_ui.cc b/chrome/browser/ui/webui/print_preview_ui.cc
index 89bcab0bd9760b9878a2cc0afb779242bbf40abc..339a5067388ae5f9122bab8870fee0247749751a 100644
--- a/chrome/browser/ui/webui/print_preview_ui.cc
+++ b/chrome/browser/ui/webui/print_preview_ui.cc
@@ -16,9 +16,9 @@
 PrintPreviewUI::PrintPreviewUI(TabContents* contents)
     : ChromeWebUI(contents),
       initial_preview_start_time_(base::TimeTicks::Now()) {
-  // PrintPreviewUI owns |handler|.
-  PrintPreviewHandler* handler = new PrintPreviewHandler();
-  AddMessageHandler(handler->Attach(this));
+  // WebUI owns |handler_|.
+  handler_ = new PrintPreviewHandler();
+  AddMessageHandler(handler_->Attach(this));
 
   // Set up the chrome://print/ data source.
   contents->profile()->GetChromeURLDataManager()->AddDataSource(
@@ -69,6 +69,10 @@ void PrintPreviewUI::OnPreviewDataIsAvailable(int expected_pages_count,
                          is_preview_modifiable, ui_identifier);
 }
 
+void PrintPreviewUI::OnNavigation() {
+  handler_->OnNavigation();
+}
+
 void PrintPreviewUI::OnFileSelectionCancelled() {
   CallJavascriptFunction("fileSelectionCancelled");
 }