Let the incognito window print.

chrome/browser/chromeos/printing/printer_pref_manager_factory.h

Index: chrome/browser/chromeos/printing/printer_pref_manager_factory.h
diff --git a/chrome/browser/chromeos/printing/printer_pref_manager_factory.h b/chrome/browser/chromeos/printing/printer_pref_manager_factory.h
index 5815eb1d33aae5445c296b84e62df6b974a610e0..f10c2f8e794c8d7d1ab2a5d130eca7f314917a7c 100644
--- a/chrome/browser/chromeos/printing/printer_pref_manager_factory.h
+++ b/chrome/browser/chromeos/printing/printer_pref_manager_factory.h
@@ -23,6 +23,10 @@ class PrinterPrefManagerFactory : public BrowserContextKeyedServiceFactory {
 
   static PrinterPrefManagerFactory* GetInstance();
 
+ protected:
+  content::BrowserContext* GetBrowserContextToUse(
+      content::BrowserContext* context) const override;
+
  private:
   friend struct base::DefaultLazyInstanceTraits<PrinterPrefManagerFactory>;