Print preview page selection should not require a rerendering of draft pages.

chrome/browser/ui/webui/print_preview_ui.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_UI_WEBUI_PRINT_PREVIEW_UI_H_
 #define CHROME_BROWSER_UI_WEBUI_PRINT_PREVIEW_UI_H_
 #pragma once
 
 #include <string>
 
@@ skipping 23 matching lines @@
                                    scoped_refptr<RefCountedBytes>* data);
 
   // Sets the print preview |data|. |index| is zero-based, and can be
   // |printing::COMPLETE_PREVIEW_DOCUMENT_INDEX| to set the entire preview
   // document.
   void SetPrintPreviewDataForIndex(int index, const RefCountedBytes* data);
 
   // Clear the existing print preview data.
   void ClearAllPreviewData();
 
+  // Returns the available draft page count.
+  int GetAvailableDraftPageCount();
+
   // Setters
   void SetInitiatorTabURLAndTitle(const std::string& initiator_url,
                                   const string16& initiator_tab_title);
 
   // Determines whether to cancel a print preview request based on
   // |preview_ui_addr| and |request_id|.
   // Can be called from any thread.
   static void GetCurrentPrintPreviewStatus(const std::string& preview_ui_addr,
                                            int request_id,
                                            bool* cancel);
@@ skipping 19 matching lines @@
   // Notifies the Web UI that the 0-based page |page_number| has been rendered.
   // |preview_request_id| indicates wich request resulted in this response.
   void OnDidPreviewPage(int page_number, int preview_request_id);
 
   // Notifies the Web UI renderer that preview data is available.
   // |expected_pages_count| specifies the total number of pages.
   // |preview_request_id| indicates which request resulted in this response.
   void OnPreviewDataIsAvailable(int expected_pages_count,
                                 int preview_request_id);
 
+  // Notifies the Web UI renderer to reuse the preview data.
+  // |preview_request_id| indicates which request resulted in this response.
   void OnReusePreviewData(int preview_request_id);
 
   // Notifies the Web UI that preview tab is destroyed. This is the last chance
   // to communicate with the source tab before the association is erased.
   void OnTabDestroyed();
 
   // Notifies the Web UI that the print preview failed to render.
   void OnPrintPreviewFailed();
 
   // Notifies the Web UI that initiator tab is closed, so we can disable all the
@@ skipping 29 matching lines @@
   std::string initiator_url_;
 
   // Store the initiator tab title, used for populating the print preview tab
   // title.
   string16 initiator_tab_title_;
 
   DISALLOW_COPY_AND_ASSIGN(PrintPreviewUI);
 };
 
 #endif  // CHROME_BROWSER_UI_WEBUI_PRINT_PREVIEW_UI_H_