Add default PDF dpi setting

printing/printing_context.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 "printing/printing_context.h"
 
 #include "base/logging.h"
 #include "base/values.h"
 #include "printing/features/features.h"
 #include "printing/page_setup.h"
@@ skipping 47 matching lines @@
 PrintingContext::Result PrintingContext::UsePdfSettings() {
   std::unique_ptr<base::DictionaryValue> pdf_settings(
       new base::DictionaryValue);
   pdf_settings->SetBoolean(kSettingHeaderFooterEnabled, false);
   pdf_settings->SetBoolean(kSettingShouldPrintBackgrounds, false);
   pdf_settings->SetBoolean(kSettingShouldPrintSelectionOnly, false);
   pdf_settings->SetInteger(kSettingMarginsType, printing::NO_MARGINS);
   pdf_settings->SetBoolean(kSettingCollate, true);
   pdf_settings->SetInteger(kSettingCopies, 1);
   pdf_settings->SetInteger(kSettingColor, printing::COLOR);
+  pdf_settings->SetInteger(kSettingDpiHorizontal, kPointsPerInch);
+  pdf_settings->SetInteger(kSettingDpiVertical, kPointsPerInch);
   pdf_settings->SetInteger(kSettingDuplexMode, printing::SIMPLEX);
   pdf_settings->SetBoolean(kSettingLandscape, false);
   pdf_settings->SetString(kSettingDeviceName, "");
   pdf_settings->SetBoolean(kSettingPrintToPDF, true);
   pdf_settings->SetBoolean(kSettingCloudPrintDialog, false);
   pdf_settings->SetBoolean(kSettingPrintWithPrivet, false);
   pdf_settings->SetBoolean(kSettingPrintWithExtension, false);
   pdf_settings->SetInteger(kSettingScaleFactor, 100);
   pdf_settings->SetBoolean(kSettingRasterizePdf, false);
   return UpdatePrintSettings(*pdf_settings);
@@ skipping 55 matching lines @@
 #endif
 
   int page_count = 0;
   job_settings.GetInteger(kSettingPreviewPageCount, &page_count);
 
   return UpdatePrinterSettings(open_in_external_preview, show_system_dialog,
                                page_count);
 }
 
 }  // namespace printing