Adds option to enable CSS backgrounds for printing.

chrome/browser/resources/print_preview/native_layer.js

Index: chrome/browser/resources/print_preview/native_layer.js
diff --git a/chrome/browser/resources/print_preview/native_layer.js b/chrome/browser/resources/print_preview/native_layer.js
index cc4ed08191e65d4493d2f0ba53a2363be1b04134..54ec8d1cf555b4a98d23d2fdaf8f661e4a2caeab 100644
--- a/chrome/browser/resources/print_preview/native_layer.js
+++ b/chrome/browser/resources/print_preview/native_layer.js
@@ -168,7 +168,8 @@ cr.define('print_preview', function() {
         'duplex': printTicketStore.isDuplexEnabled() ?
             NativeLayer.DuplexMode.LONG_EDGE : NativeLayer.DuplexMode.SIMPLEX,
         'copies': printTicketStore.getCopies(),
-        'collate': printTicketStore.isCollateEnabled()
+        'collate': printTicketStore.isCollateEnabled(),
+        'shouldPrintBackgrounds': printTicketStore.isCssBackgroundEnabled()
       };
 
       // Set 'cloudPrintID' only if the destination is not local.
@@ -225,6 +226,7 @@ cr.define('print_preview', function() {
             NativeLayer.DuplexMode.LONG_EDGE : NativeLayer.DuplexMode.SIMPLEX,
         'copies': printTicketStore.getCopies(),
         'collate': printTicketStore.isCollateEnabled(),
+        'shouldPrintBackgrounds': printTicketStore.isCssBackgroundEnabled(),
         'previewModifiable': printTicketStore.isDocumentModifiable,
         'printToPDF': destination.id ==
             print_preview.Destination.GooglePromotedId.SAVE_AS_PDF,