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

chrome/browser/printing/print_preview_message_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/printing/print_preview_message_handler.h"
 
 #include <vector>
 
 #include "base/memory/ref_counted.h"
 #include "base/memory/ref_counted_memory.h"
@@ skipping 77 matching lines @@
     NOTREACHED();
     return;
   }
 
   TabContents* print_preview_tab = GetPrintPreviewTab();
   if (!print_preview_tab || !print_preview_tab->web_ui())
     return;
 
   PrintPreviewUI* print_preview_ui =
       static_cast<PrintPreviewUI*>(print_preview_tab->web_ui());
+
+  if (!params.is_modifiable || params.clear_preview_data)
+    print_preview_ui->ClearAllPreviewData();
+
   print_preview_ui->OnDidGetPreviewPageCount(params);
 }
 
 void PrintPreviewMessageHandler::OnDidPreviewPage(
     const PrintHostMsg_DidPreviewPage_Params& params) {
   TabContents* print_preview_tab = GetPrintPreviewTab();
   if (!print_preview_tab || !print_preview_tab->web_ui())
     return;
 
   PrintPreviewUI* print_preview_ui =
       static_cast<PrintPreviewUI*>(print_preview_tab->web_ui());
   int page_number = params.page_number;
-
-  if (page_number == FIRST_PAGE_INDEX)
-    print_preview_ui->ClearAllPreviewData();
-
   if (page_number >= FIRST_PAGE_INDEX && params.data_size) {
     RefCountedBytes* data_bytes =
         GetDataFromHandle(params.metafile_data_handle, params.data_size);
     DCHECK(data_bytes);
 
     print_preview_ui->SetPrintPreviewDataForIndex(page_number, data_bytes);
     print_preview_ui->OnDidPreviewPage(page_number, params.preview_request_id);
   }
 }
 
-void PrintPreviewMessageHandler::OnPagesReadyForPreview(
+void PrintPreviewMessageHandler::OnMetafileReadyForPrinting(
     const PrintHostMsg_DidPreviewDocument_Params& params) {
   // Always try to stop the worker.
   StopWorker(params.document_cookie);
 
   if (params.expected_pages_count <= 0) {
     NOTREACHED();
     return;
   }
 
   // Get the print preview tab.
@@ skipping 79 matching lines @@
 bool PrintPreviewMessageHandler::OnMessageReceived(
     const IPC::Message& message) {
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP(PrintPreviewMessageHandler, message)
     IPC_MESSAGE_HANDLER(PrintHostMsg_RequestPrintPreview,
                         OnRequestPrintPreview)
     IPC_MESSAGE_HANDLER(PrintHostMsg_DidGetPreviewPageCount,
                         OnDidGetPreviewPageCount)
     IPC_MESSAGE_HANDLER(PrintHostMsg_DidPreviewPage,
                         OnDidPreviewPage)
-    IPC_MESSAGE_HANDLER(PrintHostMsg_PagesReadyForPreview,
-                        OnPagesReadyForPreview)
+    IPC_MESSAGE_HANDLER(PrintHostMsg_MetafileReadyForPrinting,
+                        OnMetafileReadyForPrinting)
     IPC_MESSAGE_HANDLER(PrintHostMsg_PrintPreviewFailed,
                         OnPrintPreviewFailed)
     IPC_MESSAGE_HANDLER(PrintHostMsg_DidGetDefaultPageLayout,
                         OnDidGetDefaultPageLayout)
     IPC_MESSAGE_HANDLER(PrintHostMsg_PrintPreviewCancelled,
                         OnPrintPreviewCancelled)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
   return handled;
 }
 
 void PrintPreviewMessageHandler::DidStartLoading() {
   if (tab_contents()->delegate() &&
       printing::PrintPreviewTabController::IsPrintPreviewTab(tab_contents())) {
     tab_contents()->SetContentRestrictions(CONTENT_RESTRICTION_PRINT);
   }
 }
 
 }  // namespace printing