Async frame preparation for Preview with support if selection.

chrome/renderer/printing/print_web_view_helper_mac.mm

 // Copyright (c) 2012 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/renderer/printing/print_web_view_helper.h"
 
 #import <AppKit/AppKit.h>
 
 #include "base/logging.h"
 #include "base/mac/scoped_nsautorelease_pool.h"
@@ skipping 59 matching lines @@
       print_preview_context_.set_error(
           PREVIEW_ERROR_MAC_DRAFT_METAFILE_INIT_FAILED);
       LOG(ERROR) << "Draft PreviewMetafile Init failed";
       return false;
     }
     initial_render_metafile = draft_metafile.get();
   }
 
   base::TimeTicks begin_time = base::TimeTicks::Now();
   gfx::Size page_size;
-  RenderPage(printParams, page_number, print_preview_context_.frame(), true,
-             initial_render_metafile, &page_size, NULL);
+  RenderPage(printParams, page_number, print_preview_context_.prepared_frame(),
+             true, initial_render_metafile, &page_size, NULL);
   print_preview_context_.RenderedPreviewPage(
       base::TimeTicks::Now() - begin_time);
 
   if (draft_metafile.get()) {
     draft_metafile->FinishDocument();
   } else {
     if (print_preview_context_.IsModifiable() &&
         print_preview_context_.generate_draft_pages()) {
       DCHECK(!draft_metafile.get());
       draft_metafile.reset(
@@ skipping 46 matching lines @@
     }
     RenderPageContent(frame, page_number, canvas_area, content_area,
                       scale_factor, canvas_ptr);
   }
 
   // Done printing. Close the device context to retrieve the compiled metafile.
   metafile->FinishPage();
 }
 
 }  // namespace printing