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

chrome/browser/printing/print_view_manager.h

Index: chrome/browser/printing/print_view_manager.h
diff --git a/chrome/browser/printing/print_view_manager.h b/chrome/browser/printing/print_view_manager.h
index 308400dba0323195c7feab8b33675c8640ceaa6a..684c5739e6df9728fe71ae192ed798db10faa12a 100644
--- a/chrome/browser/printing/print_view_manager.h
+++ b/chrome/browser/printing/print_view_manager.h
@@ -22,6 +22,7 @@ namespace printing {
 class JobEventDetails;
 class PrintJob;
 class PrintJobWorkerOwner;
+class PrintViewManagerObserver;
 
 // Manages the print commands in relation to a TabContents. TabContents
 // delegates a few printing related commands to this instance.
@@ -50,6 +51,11 @@ class PrintViewManager : public NotificationObserver,
   // Handles cancelled preview printing request.
   void PreviewPrintingRequestCancelled();
 
+  // Sets |observer| as the current PrintViewManagerObserver. Pass in NULL to
+  // remove the current observer. |observer| may always be NULL, but |observer_|
+  // must be NULL if |observer| is non-NULL.
+  void set_observer(PrintViewManagerObserver* observer);
+
   // PrintedPagesSource implementation.
   virtual string16 RenderSourceName();
   virtual GURL RenderSourceUrl();
@@ -71,6 +77,7 @@ class PrintViewManager : public NotificationObserver,
  private:
   // IPC Message handlers.
   void OnDidGetPrintedPagesCount(int cookie, int number_pages);
+  void OnDidShowPrintDialog();
   void OnDidPrintPage(const PrintHostMsg_DidPrintPage_Params& params);
   void OnPrintingFailed(int cookie);
 
@@ -150,6 +157,10 @@ class PrintViewManager : public NotificationObserver,
   bool is_title_overridden_;
   string16 overridden_title_;
 
+  // Weak pointer to an observer that is notified when the print dialog is
+  // shown.
+  PrintViewManagerObserver* observer_;
+
   DISALLOW_COPY_AND_ASSIGN(PrintViewManager);
 };