Cleanup LocalDiscoveryUIHandler.

chrome/browser/extensions/api/cloud_print_private/cloud_print_private_api.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/extensions/api/cloud_print_private/cloud_print_private_api.h"
 
 #include <string>
 
 #include "base/threading/sequenced_worker_pool.h"
 #include "chrome/browser/printing/cloud_print/cloud_print_proxy_service.h"
@@ skipping 30 matching lines @@
 #if defined(ENABLE_PRINT_PREVIEW)
   using api::cloud_print_private::SetupConnector::Params;
   std::unique_ptr<Params> params(Params::Create(*args_));
   if (CloudPrintTestsDelegate::instance()) {
     CloudPrintTestsDelegate::instance()->SetupConnector(
         params->user_email,
         params->robot_email,
         params->credentials,
         params->user_settings);
   } else {
+    std::unique_ptr<base::DictionaryValue> user_settings(
+        params->user_settings.ToValue());
     CloudPrintProxyService* service =
         CloudPrintProxyServiceFactory::GetForProfile(GetProfile());
-    if (!service)
-      return false;

[Vitaly Buka (NO REVIEWS), 2016/04/16 01:33:52]

I guess this could be NULL for for incognito.

[Lei Zhang, 2016/04/16 01:53:19]

Ok, I will look into this. How is this API used anyway?

At least I passed all the existing tests. Should I add another API test and try
to use it in incognito?

At least my thought right now is:

- GetProfile() relies on UIThreadExtensionFunction's context.
- UIThreadExtensionFunction's context starts out NULL, but 
ExtensionFunctionDispatcher calls
UIThreadExtensionFunction::set_browser_context() before running any functions.
- ExtensionFunctionDispatcher's context comes from ExtensionWebContentsObserver.
- ExtensionFunctionDispatcher's context comes from a WebContents.
- WebContents should have a valid context?

[Vitaly Buka (NO REVIEWS), 2016/04/16 02:17:56]

Test would be nice.

This API used only by
https://www.google.com/cloudprint/enable_chrome_connector/enable.html.
chrome://devices only redirects to that page.

Try to navigate to
https://www.google.com/cloudprint/enable_chrome_connector/enable.html?proxy=N...

In normal tab you should see printers list. and "add" button.
Incognito should not crash. Now it displays empty list of printers and no "add"
button.
I suspect it will crash without if (!service).

If you know how disable API for incognito, then you probably can remove if
(!service).

-    std::unique_ptr<base::DictionaryValue> user_setings(
-        params->user_settings.ToValue());
     service->EnableForUserWithRobot(params->credentials,
                                     params->robot_email,
                                     params->user_email,
-                                    *user_setings);
+                                    *user_settings);
   }
   SendResponse(true);
   return true;
 #else
   return false;
 #endif
 }
 
 CloudPrintPrivateGetHostNameFunction::CloudPrintPrivateGetHostNameFunction() {
 }
@@ skipping 21 matching lines @@
   results_ = api::cloud_print_private::GetPrinters::Results::Create(printers);
   SendResponse(true);
 }
 
 bool CloudPrintPrivateGetPrintersFunction::RunAsync() {
 #if defined(ENABLE_PRINT_PREVIEW)
   std::vector<std::string> result;
   if (CloudPrintTestsDelegate::instance()) {
     SendResults(CloudPrintTestsDelegate::instance()->GetPrinters());
   } else {
-    CloudPrintProxyService* service =
-        CloudPrintProxyServiceFactory::GetForProfile(GetProfile());
-    if (!service)
-      return false;
-    service->GetPrinters(
+    CloudPrintProxyServiceFactory::GetForProfile(GetProfile())->GetPrinters(
         base::Bind(&CloudPrintPrivateGetPrintersFunction::SendResults, this));
   }
   return true;
 #else
   return false;
 #endif
 }
 
 
 CloudPrintPrivateGetClientIdFunction::CloudPrintPrivateGetClientIdFunction() {
 }
 
 CloudPrintPrivateGetClientIdFunction::~CloudPrintPrivateGetClientIdFunction() {
 }
 
 bool CloudPrintPrivateGetClientIdFunction::RunAsync() {
   SetResult(new base::StringValue(
       CloudPrintTestsDelegate::instance() ?
       CloudPrintTestsDelegate::instance()->GetClientId() :
       google_apis::GetOAuth2ClientID(google_apis::CLIENT_CLOUD_PRINT)));
   SendResponse(true);
   return true;
 }
 
 }  // namespace extensions