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

chrome/renderer/print_web_view_helper.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_PRINT_WEB_VIEW_HELPER_H_
 #define CHROME_RENDERER_PRINT_WEB_VIEW_HELPER_H_
 #pragma once
 
-#include <utility>
 #include <vector>
 
 #include "base/memory/scoped_ptr.h"
 #include "base/shared_memory.h"
 #include "base/time.h"
 #include "content/renderer/render_view_observer.h"
 #include "content/renderer/render_view_observer_tracker.h"
 #include "printing/metafile.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebFrameClient.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebNode.h"
@@ skipping 108 matching lines @@
   void OnPrintForSystemDialog();
 
   // Initiate print preview.
   void OnInitiatePrintPreview();
 
   // Start the process of generating a print preview using |settings|.
   void OnPrintPreview(const base::DictionaryValue& settings);
   // Initialize the print preview document.
   bool CreatePreviewDocument();
 
-  // Continue generating the print preview. |requested_preview_page_index|
-  // specifies the browser requested preview page index. It is 1-based or
-  // |printing::INVALID_PAGE_INDEX| to continue with next page.
-  void OnContinuePreview(int requested_preview_page_index);
+  // Continue generating the print preview.
+  void OnContinuePreview();
   // Renders a print preview page. |page_number| is 0-based.
   void RenderPreviewPage(int page_number);
   // Finalize the print preview document.
   bool FinalizePreviewDocument();
 
   // Abort the preview to put |print_preview_context_| into the 'UNINITIALIZED'
   // state.
   void OnAbortPreview();
 
   // Print / preview the node under the context menu.
@@ skipping 133 matching lines @@
 
   // Notify the browser a print preview page has been rendered.
   // |page_number| is 0-based or |printing::INVALID_PAGE_INDEX| to check
   // for pending preview requests.
   void PreviewPageRendered(int page_number, printing::Metafile* metafile);
 
   WebKit::WebView* print_web_view_;
 
   scoped_ptr<PrintMsg_PrintPages_Params> print_pages_params_;
   bool is_preview_;
+  bool is_complete_metafile_sent_;
 
   // Used for scripted initiated printing blocking.
   base::Time last_cancelled_script_print_;
   int user_cancelled_scripted_print_count_;
 
   // Let the browser process know of a printing failure. Only set to false when
   // the failure came from the browser in the first place.
   bool notify_browser_of_print_failure_;
 
   scoped_ptr<PrintMsg_PrintPages_Params> old_print_pages_params_;
@@ skipping 13 matching lines @@
     void OnPrintPreview();
 
     // Create the print preview document. |pages| is empty to print all pages.
     bool CreatePreviewDocument(PrintMsg_Print_Params* params,
                                const std::vector<int>& pages);
 
     // Called after a page gets rendered. |page_time| is how long the
     // rendering took.
     void RenderedPreviewPage(const base::TimeDelta& page_time);
 
+    // Updates the print preview context when the required pages are rendered.
+    void PreviewPagesRendered();
+
     // Finalizes the print preview document.
     void FinalizePreviewDocument();
 
     // Cleanup after print preview finishes.
     void Finished();
 
     // Cleanup after print preview fails.
     void Failed();
 
     // Abort the print preview.
     void Abort();
 
     // Helper functions
     int GetNextPageNumber();
     bool IsReadyToRender() const;
     bool IsBusy() const;
     bool IsModifiable() const;
+    bool IsLastPageOfCompleteMetafile() const;
+    bool IsFinalPageRendered() const;
+
+    // Setters
+    void set_generate_draft_pages(bool generate_draft_pages);
 
     // Getters
     WebKit::WebFrame* frame() const;
     WebKit::WebNode* node() const;
     int total_page_count() const;
+    bool generate_draft_pages();
     printing::Metafile* metafile() const;
     const PrintMsg_Print_Params& print_params() const;
     const gfx::Size& GetPrintCanvasSize() const;
 
    private:
     enum State {
       UNINITIALIZED,  // Not ready to render.
       INITIALIZED,    // Ready to render.
       RENDERING,      // Rendering.
       DONE            // Finished rendering.
     };
 
     // Reset some of the internal rendering context.
     void ClearContext();
 
     // Specifies what to render for print preview.
     WebKit::WebFrame* frame_;
     scoped_ptr<WebKit::WebNode> node_;
 
     scoped_ptr<PrepareFrameAndViewForPrint> prep_frame_view_;
     scoped_ptr<printing::Metafile> metafile_;
     scoped_ptr<PrintMsg_Print_Params> print_params_;
 
     // Total page count in the renderer.
     int total_page_count_;
 
-    // Number of pages to render.
-    int actual_page_count_;
+    // List of page indices that need to be rendered.
+    std::vector<int> render_page_list_;
 
-    // The current page to render.
-    int current_page_number_;
+    // Specifies the current list index.
+    int render_page_list_index_;
 
-    // |rendered_pages_| tracks which pages need to be printed as well as
-    // the page slot it should be printed in. See GetPageSlotForPage.
-    typedef std::pair<bool, int> PreviewPageInfo;
-    std::vector<PreviewPageInfo> rendered_pages_;
+    // True, when draft pages needs to be generated.
+    bool generate_draft_pages_;
+
+    // Specifies the total number of pages in the complete metafile.
+    int complete_metafile_page_count_;
 
     base::TimeDelta document_render_time_;
     base::TimeTicks begin_time_;
 
     State state_;
   };
 
   PrintPreviewContext print_preview_context_;
 
   DISALLOW_COPY_AND_ASSIGN(PrintWebViewHelper);
 };
 
 #endif  // CHROME_RENDERER_PRINT_WEB_VIEW_HELPER_H_