Adds option to enable CSS backgrounds for printing.

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/page_setup.h"
 #include "printing/page_size_margins.h"
@@ skipping 60 matching lines @@
     margins_in_points.top = page_size_margins.margin_top;
     margins_in_points.bottom = page_size_margins.margin_bottom;
     margins_in_points.left = page_size_margins.margin_left;
     margins_in_points.right = page_size_margins.margin_right;
 
     settings_.SetCustomMargins(margins_in_points);
   }
 
   PrintingContext::Result result = UpdatePrinterSettings(job_settings, ranges);
   PrintSettingsInitializer::InitHeaderFooterStrings(job_settings, &settings_);
+
+  if (!job_settings.GetBoolean(kSettingShouldPrintBackgrounds,
+                               &settings_.should_print_backgrounds)) {
+    NOTREACHED();
+  }
+
   return result;
 }
 
 }  // namespace printing