Allow the PrinterDetector to be constructed with a delegated profile.

chrome/browser/chromeos/printer_detector/printer_detector_factory.cc

Index: chrome/browser/chromeos/printer_detector/printer_detector_factory.cc
diff --git a/chrome/browser/chromeos/printer_detector/printer_detector_factory.cc b/chrome/browser/chromeos/printer_detector/printer_detector_factory.cc
index 49c02a680935189a3a2eaee0a90bcc91d402a185..4e5dc7078b6dc1d69057de3586b5b05055c20106 100644
--- a/chrome/browser/chromeos/printer_detector/printer_detector_factory.cc
+++ b/chrome/browser/chromeos/printer_detector/printer_detector_factory.cc
@@ -7,6 +7,7 @@
 #include "base/command_line.h"
 #include "chrome/browser/chromeos/printer_detector/printer_detector.h"
 #include "chrome/browser/chromeos/printing/printers_manager_factory.h"
+#include "chrome/browser/profiles/incognito_helpers.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/common/chrome_switches.h"
 #include "components/keyed_service/content/browser_context_dependency_manager.h"
@@ -43,6 +44,11 @@ PrinterDetectorFactory::PrinterDetectorFactory()
 PrinterDetectorFactory::~PrinterDetectorFactory() {
 }
 
+content::BrowserContext* PrinterDetectorFactory::GetBrowserContextToUse(
+    content::BrowserContext* context) const {
+  return chrome::GetBrowserContextRedirectedInIncognito(context);
+}
+
 KeyedService* PrinterDetectorFactory::BuildServiceInstanceFor(
     content::BrowserContext* context) const {
   if (base::CommandLine::ForCurrentProcess()->HasSwitch(