Reverting 27379.

chrome/browser/printing/printer_query.h

Index: chrome/browser/printing/printer_query.h
===================================================================
--- chrome/browser/printing/printer_query.h	(revision 27386)
+++ chrome/browser/printing/printer_query.h	(working copy)
@@ -6,6 +6,7 @@
 #define CHROME_BROWSER_PRINTING_PRINTER_QUERY_H_
 
 #include "base/scoped_ptr.h"
+#include "base/ref_counted.h"
 #include "chrome/browser/printing/print_job_worker_owner.h"
 
 class CancelableTask;
@@ -20,7 +21,8 @@
 class PrintJobWorker;
 
 // Query the printer for settings.
-class PrinterQuery : public PrintJobWorkerOwner {
+class PrinterQuery : public base::RefCountedThreadSafe<PrinterQuery>,
+                     public PrintJobWorkerOwner {
  public:
   // GetSettings() UI parameter.
   enum GetSettingsAskParam {
@@ -32,6 +34,12 @@
   virtual ~PrinterQuery();
 
   // PrintJobWorkerOwner
+  virtual void AddRef() {
+    return base::RefCountedThreadSafe<PrinterQuery>::AddRef();
+  }
+  virtual void Release() {
+    return base::RefCountedThreadSafe<PrinterQuery>::Release();
+  }
   virtual void GetSettingsDone(const PrintSettings& new_settings,
                                PrintingContext::Result result);
   virtual PrintJobWorker* DetachWorker(PrintJobWorkerOwner* new_owner);