Print Preview: Hook up the print button to initiate printing without displaying a print dialog.

chrome/browser/printing/printer_query.h

Index: chrome/browser/printing/printer_query.h
diff --git a/chrome/browser/printing/printer_query.h b/chrome/browser/printing/printer_query.h
index edc0c63e319c76b1cc3e002c809670fdb5f802d3..ad0df6a9b7aabecbafac76a0b5eddf75d19befe1 100644
--- a/chrome/browser/printing/printer_query.h
+++ b/chrome/browser/printing/printer_query.h
@@ -51,6 +51,11 @@ class PrinterQuery : public PrintJobWorkerOwner {
                    bool use_overlays,
                    CancelableTask* callback);
 
+  // Updates the current settings with |new_settings|. |new_settings| is a json
+  // string.
+  void SetSettings(const std::string& new_settings,
+                   CancelableTask* callback);
+
   // Stops the worker thread since the client is done with this object.
   void StopWorker();