Rasterize page before printing.

chrome/renderer/print_web_view_helper.h

 // 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.
 
 #ifndef CHROME_RENDERER_PRINT_WEB_VIEW_HELPER_H_
 #define CHROME_RENDERER_PRINT_WEB_VIEW_HELPER_H_
 
 #include <vector>
 
 #include "base/gtest_prod_util.h"
@@ skipping 251 matching lines @@
                          const gfx::Size& canvas_size,
                          WebKit::WebFrame* frame);
 #endif
 
   // Render the frame for printing.
   bool RenderPagesForPrint(WebKit::WebFrame* frame,
                            const WebKit::WebNode& node);
 
   // Platform specific helper function for rendering page(s) to |metafile|.
 #if defined(OS_WIN)
-  // Because of mixed support for alpha channels on printers, this method may
-  // need to create a new metafile.  The result may be either the passed
-  // |metafile| or a new one.  In either case, the caller owns both |metafile|
-  // and the result.
-  printing::Metafile* RenderPage(const PrintMsg_Print_Params& params,
-                                 int page_number,
-                                 WebKit::WebFrame* frame,
-                                 bool is_preview,
-                                 printing::Metafile* metafile,
-                                 double* scale_factor,
-                                 gfx::Size* page_size_in_dpi,
-                                 gfx::Rect* content_area_in_dpi);
+  void RenderPage(const PrintMsg_Print_Params& params,
+                  int page_number,
+                  WebKit::WebFrame* frame,
+                  bool is_preview,
+                  printing::Metafile* metafile,
+                  double* scale_factor,
+                  gfx::Size* page_size_in_dpi,
+                  gfx::Rect* content_area_in_dpi);
 #elif defined(OS_MACOSX)
   void RenderPage(const PrintMsg_Print_Params& params, int page_number,
                   WebKit::WebFrame* frame, bool is_preview,
                   printing::Metafile* metafile, gfx::Size* page_size,
                   gfx::Rect* content_rect);
 #elif defined(OS_POSIX)
   bool RenderPages(const PrintMsg_PrintPages_Params& params,
                    WebKit::WebFrame* frame, const WebKit::WebNode& node,
                    int* page_count, PrepareFrameAndViewForPrint* prepare,
                    printing::Metafile* metafile);
@@ skipping 190 matching lines @@
     enum PrintPreviewErrorBuckets error_;
 
     State state_;
   };
 
   PrintPreviewContext print_preview_context_;
   DISALLOW_COPY_AND_ASSIGN(PrintWebViewHelper);
 };
 
 #endif  // CHROME_RENDERER_PRINT_WEB_VIEW_HELPER_H_