When printing a PDF, query and use the print scaling disabled option.

chrome/renderer/print_web_view_helper.h

 // 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.
 
 #ifndef CHROME_RENDERER_PRINT_WEB_VIEW_HELPER_H_
 #define CHROME_RENDERER_PRINT_WEB_VIEW_HELPER_H_
 #pragma once
 
 #include <vector>
 
@@ skipping 163 matching lines @@
       WebKit::WebFrame* frame,
       const WebKit::WebNode& node,
       scoped_ptr<PrepareFrameAndViewForPrint>* prepare);
 
   // Update the current print settings with new |job_settings|. |job_settings|
   // dictionary contains print job details such as printer name, number of
   // copies, page range, etc.
   bool UpdatePrintSettings(WebKit::WebFrame* frame,
                            const WebKit::WebNode& node,
                            const base::DictionaryValue& passed_job_settings,
-                           bool generating_preview);
+                           bool print_for_preview);
 
   // Get final print settings from the user.
   // Return false if the user cancels or on error.
   bool GetPrintSettingsFromUser(WebKit::WebFrame* frame,
+                                const WebKit::WebNode& node,
                                 int expected_pages_count,
                                 bool use_browser_overlays);
 
   // Page Printing / Rendering ------------------------------------------------
 
   // Prints all the pages listed in |params|.
   // It will implicitly revert the document to display CSS media type.
   bool PrintPages(const PrintMsg_PrintPages_Params& params,
                   WebKit::WebFrame* frame,
                   const WebKit::WebNode& node,
@@ skipping 96 matching lines @@
   // Notifies the browser a print preview page has been rendered.
   // |page_number| is 0-based.
   // For a valid |page_number| with modifiable content,
   // |metafile| is the rendered page. Otherwise |metafile| is NULL.
   // Returns true if print preview should continue, false on failure.
   bool PreviewPageRendered(int page_number, printing::Metafile* metafile);
 
   WebKit::WebView* print_web_view_;
 
   scoped_ptr<PrintMsg_PrintPages_Params> print_pages_params_;
-  bool is_preview_;
+  bool is_preview_enabled_;
   bool is_print_ready_metafile_sent_;
 
   // Used for scripted initiated printing blocking.
   base::Time last_cancelled_script_print_;
   int user_cancelled_scripted_print_count_;
 
   // Let the browser process know of a printing failure. Only set to false when
   // the failure came from the browser in the first place.
   bool notify_browser_of_print_failure_;
 
@@ skipping 45 matching lines @@
     void FinalizePrintReadyDocument();
 
     // Cleanup after print preview finishes.
     void Finished();
 
     // Cleanup after print preview fails.
     void Failed(bool report_error);
 
     // Helper functions
     int GetNextPageNumber();
-    bool IsReadyToRender() const;
+    bool IsRendering() const;
     bool IsModifiable() const;
     bool IsLastPageOfPrintReadyMetafile() const;
     bool IsFinalPageRendered() const;
 
     // Setters
     void set_generate_draft_pages(bool generate_draft_pages);
     void set_error(enum PrintPreviewErrorBuckets error);
 
     // Getters
     WebKit::WebFrame* frame() const;
@@ skipping 46 matching lines @@
 
     State state_;
   };
 
   PrintPreviewContext print_preview_context_;
 
   DISALLOW_COPY_AND_ASSIGN(PrintWebViewHelper);
 };
 
 #endif  // CHROME_RENDERER_PRINT_WEB_VIEW_HELPER_H_