Print Preview: Make preview generation event driven to eliminate synchronous messages.

chrome/renderer/mock_render_thread.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_RENDERER_MOCK_RENDER_THREAD_H_
 #define CHROME_RENDERER_MOCK_RENDER_THREAD_H_
 #pragma once
 
 #include <string>
 
@@ skipping 65 matching lines @@
   // state.
   void SendCloseMessage();
 
   // Returns the pseudo-printer instance.
   MockPrinter* printer() const { return printer_.get(); }
 
   // Call with |response| set to true if the user wants to print.
   // False if the user decides to cancel.
   void set_print_dialog_user_response(bool response);
 
-  // Set to true to simulate canceling of a print preview.
-  void set_cancel_print_preview(bool cancel);
+  // Get the number of pages to generate for print preview.
+  int print_preview_pages_remaining();
 
  private:
   // This function operates as a regular IPC listener.
   bool OnMessageReceived(const IPC::Message& msg);
 
   // The Widget expects to be returned valid route_id.
   void OnMsgCreateWidget(int opener_id,
                          WebKit::WebPopupType popup_type,
                          int* route_id);
 
@@ skipping 19 matching lines @@
 
   // PrintWebViewHelper expects default print settings.
   void OnGetDefaultPrintSettings(PrintMsg_Print_Params* setting);
 
   // PrintWebViewHelper expects final print settings from the user.
   void OnScriptedPrint(const PrintHostMsg_ScriptedPrint_Params& params,
                        PrintMsg_PrintPages_Params* settings);
 
   void OnDidGetPrintedPagesCount(int cookie, int number_pages);
   void OnDidPrintPage(const PrintHostMsg_DidPrintPage_Params& params);
-  void OnDidPreviewPage(int page_number, bool* cancel);
+  void OnDidGetPreviewPageCount(int document_cookie, int number_pages);
+  void OnDidPreviewPage(int page_number);
 
   // For print preview, PrintWebViewHelper will update settings.
   void OnUpdatePrintSettings(int document_cookie,
                              const DictionaryValue& job_settings,
                              PrintMsg_PrintPages_Params* params);
 
   IPC::TestSink sink_;
 
   // Routing id what will be assigned to the Widget.
   int32 routing_id_;
 
   // Opener id reported by the Widget.
   int32 opener_id_;
 
   // We only keep track of one Widget, we learn its pointer when it
   // adds a new route.
   IPC::Channel::Listener* widget_;
 
   // The last known good deserializer for sync messages.
   scoped_ptr<IPC::MessageReplyDeserializer> reply_deserializer_;
 
   // A mock printer device used for printing tests.
   scoped_ptr<MockPrinter> printer_;
 
   // True to simulate user clicking print. False to cancel.
   bool print_dialog_user_response_;
 
-  // True to simulate cancelling a print preview.
-  bool cancel_print_preview_;
+  // Number of pages to generate for print preview.
+  int print_preview_pages_remaining_;
 };
 
 #endif  // CHROME_RENDERER_MOCK_RENDER_THREAD_H_