add print to pdf for headless

components/printing/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 COMPONENTS_PRINTING_RENDERER_PRINT_WEB_VIEW_HELPER_H_
 #define COMPONENTS_PRINTING_RENDERER_PRINT_WEB_VIEW_HELPER_H_
 
 #include <memory>
 #include <vector>
 
@@ skipping 90 matching lines @@
     // The default implementation returns |true|.
     virtual bool IsAskPrintSettingsEnabled();
 
     // If false, window.print() won't do anything.
     // The default implementation returns |true|.
     virtual bool IsScriptedPrintEnabled();
 
     // Returns true if printing is overridden and the default behavior should be
     // skipped for |frame|.
     virtual bool OverridePrint(blink::WebLocalFrame* frame) = 0;
+
+#if defined(OS_MACOSX)
+    virtual bool UseSingleMetafile();

[Lei Zhang, 2017/04/06 08:08:42]

Explain what this does.

[jzfeng, 2017/04/06 09:01:51]

Done.

+#endif
   };
 
   PrintWebViewHelper(content::RenderFrame* render_frame,
                      std::unique_ptr<Delegate> delegate);
   ~PrintWebViewHelper() override;
 
   // Minimum valid value for scaling. Since scaling is originally an integer
   // representing a percentage, it should never be less than this if it is
   // valid.
   static constexpr double kEpsilon = 0.01f;
@@ skipping 155 matching lines @@
   void PrintPages();
   bool PrintPagesNative(blink::WebLocalFrame* frame, int page_count);
   void FinishFramePrinting();
   // Render the frame for printing.
   bool RenderPagesForPrint(blink::WebLocalFrame* frame,
                            const blink::WebNode& node);
 #endif  // BUILDFLAG(ENABLE_BASIC_PRINTING)
 
   // Prints the page listed in |params|.
 #if defined(OS_MACOSX)
-  void PrintPageInternal(const PrintMsg_PrintPage_Params& params,
-                         blink::WebLocalFrame* frame);
+  void PrintPagesInternal(const PrintMsg_PrintPage_Params& params,
+                          blink::WebLocalFrame* frame,
+                          std::vector<int> printed_pages);

[Lei Zhang, 2017/04/06 08:08:42]

Pass by const ref.

[jzfeng, 2017/04/06 09:01:51]

Done.

 #else
   void PrintPageInternal(const PrintMsg_PrintPage_Params& params,
                          blink::WebLocalFrame* frame,
                          PdfMetafileSkia* metafile,
                          gfx::Size* page_size_in_dpi,
                          gfx::Rect* content_area_in_dpi,
                          gfx::Rect* printable_area_in_dpi);
 #endif  // defined(OS_MACOSX)
 
   // Platform specific helper function for rendering page(s) to |metafile|.
@@ skipping 241 matching lines @@
   base::Closure on_stop_loading_closure_;
 
   base::WeakPtrFactory<PrintWebViewHelper> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(PrintWebViewHelper);
 };
 
 }  // namespace printing
 
 #endif  // COMPONENTS_PRINTING_RENDERER_PRINT_WEB_VIEW_HELPER_H_