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

chrome/browser/printing/print_view_manager.h

 // 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.
 
 #ifndef CHROME_BROWSER_PRINTING_PRINT_VIEW_MANAGER_H_
 #define CHROME_BROWSER_PRINTING_PRINT_VIEW_MANAGER_H_
 #pragma once
 
 #include "base/memory/ref_counted.h"
 #include "base/string16.h"
 #include "content/browser/tab_contents/tab_contents_observer.h"
 #include "content/common/notification_observer.h"
 #include "content/common/notification_registrar.h"
 #include "printing/printed_pages_source.h"
 
 class RenderViewHost;
 class TabContentsWrapper;
 struct PrintHostMsg_DidPrintPage_Params;
 
 namespace printing {
 
 class JobEventDetails;
 class PrintJob;
 class PrintJobWorkerOwner;
+class PrintViewManagerDelegate;
 
 // Manages the print commands in relation to a TabContents. TabContents
 // delegates a few printing related commands to this instance.
 class PrintViewManager : public NotificationObserver,
                          public PrintedPagesSource,
                          public TabContentsObserver {
  public:
   explicit PrintViewManager(TabContentsWrapper* tab);
   virtual ~PrintViewManager();
 
   // Override the title for this PrintViewManager's PrintJobs using the title
   // in |tab_contents|.
   void OverrideTitle(TabContents* tab_contents);
 
   // Prints the current document immediately. Since the rendering is
   // asynchronous, the actual printing will not be completed on the return of
-  // this function. Returns false if printing is impossible at the moment.
-  bool PrintNow();
+  // this function. |delegate| is optional and may be used to be notified when
+  // the print dialog is shown. Returns false if printing is impossible at the
+  // moment.
+  bool PrintNow(PrintViewManagerDelegate* delegate);

[Lei Zhang, 2011/06/21 01:54:46]

Since we expect |delegate| to be NULL most of the time, can we leave PrintNow()
as it was before and add PrintNowWithDelegate(PVMD* delegate)?

[James Hawkins, 2011/06/22 23:47:24]

I'd rather not, as that complicates the API unnecessarily by adding another
method.

 
   // Initiate print preview of the current document by first notifying the
   // renderer. Since this happens asynchronous, the print preview tab creation
   // will not be completed on the return of this function. Returns false if
   // print preview is impossible at the moment.
   bool PrintPreviewNow();
 
   // Handles cancelled preview printing request.
   void PreviewPrintingRequestCancelled();
 
@@ skipping 11 matching lines @@
 
   // Terminates or cancels the print job if one was pending.
   virtual void RenderViewGone();
 
   // Cancels the print job.
   virtual void StopNavigation();
 
  private:
   // IPC Message handlers.
   void OnDidGetPrintedPagesCount(int cookie, int number_pages);
+  void OnDidShowPrintDialog();
   void OnDidPrintPage(const PrintHostMsg_DidPrintPage_Params& params);
   void OnPrintingFailed(int cookie);
 
   // Processes a NOTIFY_PRINT_JOB_EVENT notification.
   void OnNotifyPrintJobEvent(const JobEventDetails& event_details);
 
   // Requests the RenderView to render all the missing pages for the print job.
   // Noop if no print job is pending. Returns true if at least one page has been
   // requested to the renderer.
   bool RenderAllMissingPagesNow();
@@ skipping 59 matching lines @@
 
 #if defined(OS_POSIX) && !defined(OS_MACOSX)
   // Set to true when OnDidPrintPage() should be expecting the first page.
   bool expecting_first_page_;
 #endif
 
   // Title override.
   bool is_title_overridden_;
   string16 overridden_title_;
 
+  // Weak pointer to a delegate that is notified when the print dialog is shown.
+  PrintViewManagerDelegate* delegate_;
+
   DISALLOW_COPY_AND_ASSIGN(PrintViewManager);
 };
 
 }  // namespace printing
 
 #endif  // CHROME_BROWSER_PRINTING_PRINT_VIEW_MANAGER_H_