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

chrome/browser/ui/webui/print_preview_handler.cc

 // 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.
 
 #include "chrome/browser/ui/webui/print_preview_handler.h"
 
 #include <string>
 
 #include "base/base64.h"
 #if !defined(OS_CHROMEOS)
 #include "base/command_line.h"
 #endif
 #include "base/i18n/file_util_icu.h"
 #include "base/json/json_reader.h"
 #include "base/memory/ref_counted.h"
 #include "base/metrics/histogram.h"
 #include "base/path_service.h"
+#include "base/string_number_conversions.h"
 #include "base/threading/thread.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/utf_string_conversions.h"
 #include "base/values.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/platform_util.h"
 #include "chrome/browser/printing/background_printing_manager.h"
 #include "chrome/browser/printing/cloud_print/cloud_print_url.h"
 #include "chrome/browser/printing/printer_manager_dialog.h"
 #include "chrome/browser/printing/print_preview_tab_controller.h"
@@ skipping 441 matching lines @@
                                has_logged_printers_count_);
   has_logged_printers_count_ = true;
 
   BrowserThread::PostTask(
       BrowserThread::FILE, FROM_HERE,
       NewRunnableMethod(task.get(),
                         &PrintSystemTaskProxy::EnumeratePrinters));
 }
 
 void PrintPreviewHandler::HandleGetPreview(const ListValue* args) {
+  DCHECK(args->GetSize() == 3);
   scoped_ptr<DictionaryValue> settings(GetSettingsDictionary(args));
   if (!settings.get())
     return;
   int request_id = -1;
   if (!settings->GetInteger(printing::kPreviewRequestID, &request_id))
     return;
 
   PrintPreviewUI* print_preview_ui = static_cast<PrintPreviewUI*>(web_ui_);
   print_preview_ui->OnPrintPreviewRequest(request_id);
   // Add an additional key in order to identify |print_preview_ui| later on
@@ skipping 22 matching lines @@
   if (display_header_footer) {
     settings->SetString(printing::kSettingHeaderFooterTitle,
                         initiator_tab->GetTitle());
     std::string url;
     NavigationEntry* entry = initiator_tab->controller().GetActiveEntry();
     if (entry)
       url = entry->virtual_url().spec();
     settings->SetString(printing::kSettingHeaderFooterURL, url);
   }
 
+  bool generate_draft_data = false;
+  if (!settings->GetBoolean(printing::kSettingGenerateDraftData,
+                            &generate_draft_data)) {
+    NOTREACHED();
+  }
+
+  if (!generate_draft_data) {
+    int draft_page_count = -1;
+    bool preview_modifiable = false;
+    std::string draft_page_count_str;
+    if (!args->GetString(1, &draft_page_count_str) ||
+        !base::StringToInt(draft_page_count_str, &draft_page_count)) {
+      NOTREACHED();
+      draft_page_count = -1;
+    }
+
+    if (!args->GetBoolean(2, &preview_modifiable))
+      NOTREACHED();
+
+    if (draft_page_count != -1 && preview_modifiable &&
+        print_preview_ui->GetAvailableDraftPageCount() != draft_page_count) {
+      settings->SetBoolean(printing::kSettingGenerateDraftData, true);
+    }
+  }
+
   VLOG(1) << "Print preview request start";
   RenderViewHost* rvh = initiator_tab->render_view_host();
   rvh->Send(new PrintMsg_PrintPreview(rvh->routing_id(), *settings));
 }
 
 void PrintPreviewHandler::HandlePrint(const ListValue* args) {
   ReportStats();
 
   // Record the number of times the user requests to regenerate preview data
   // before printing.
@@ skipping 414 matching lines @@
     return;
 
   // We no longer require the initiator tab details. Remove those details
   // associated with the preview tab to allow the initiator tab to create
   // another preview tab.
   printing::PrintPreviewTabController* tab_controller =
      printing::PrintPreviewTabController::GetInstance();
   if (tab_controller)
     tab_controller->EraseInitiatorTabInfo(preview_tab());
 }