Enable file_system_provider::Service in incognito.

chrome/browser/chromeos/file_system_provider/service_factory.cc

Index: chrome/browser/chromeos/file_system_provider/service_factory.cc
diff --git a/chrome/browser/chromeos/file_system_provider/service_factory.cc b/chrome/browser/chromeos/file_system_provider/service_factory.cc
index 8669ff9e06d6fcbe7b2d4b601974ea90ab97b981..7322376bc2d0855cb5427549387535f6d76ac72e 100644
--- a/chrome/browser/chromeos/file_system_provider/service_factory.cc
+++ b/chrome/browser/chromeos/file_system_provider/service_factory.cc
@@ -6,6 +6,7 @@
 
 #include "chrome/browser/chromeos/file_system_provider/service.h"
 #include "chrome/browser/extensions/extension_system_factory.h"
+#include "chrome/browser/profiles/incognito_helpers.h"
 #include "components/keyed_service/content/browser_context_dependency_manager.h"
 #include "extensions/browser/extension_registry.h"
 #include "extensions/browser/extension_registry_factory.h"
@@ -48,5 +49,10 @@ KeyedService* ServiceFactory::BuildServiceInstanceFor(
 
 bool ServiceFactory::ServiceIsCreatedWithBrowserContext() const { return true; }
 
+content::BrowserContext* ServiceFactory::GetBrowserContextToUse(
+    content::BrowserContext* context) const {
+  return chrome::GetBrowserContextRedirectedInIncognito(context);
+}
+
 }  // namespace file_system_provider
 }  // namespace chromeos