Fix chrome://site-engagement in incognito mode.

chrome/browser/ui/webui/engagement/site_engagement_ui.cc

 // Copyright 2015 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/ui/webui/engagement/site_engagement_ui.h"
 
 #include <cmath>
 #include <utility>
 
 #include "base/macros.h"
@@ skipping 58 matching lines @@
 
   mojo::Binding<SiteEngagementUIHandler> binding_;
 
   DISALLOW_COPY_AND_ASSIGN(SiteEngagementUIHandlerImpl);
 };
 
 }  // namespace
 
 SiteEngagementUI::SiteEngagementUI(content::WebUI* web_ui)
     : MojoWebUIController<SiteEngagementUIHandler>(web_ui) {
+  // Incognito profiles will not have a site engagement service.
+  Profile* profile = Profile::FromWebUI(web_ui);
+  if (!SiteEngagementService::Get(profile))
+    return;

[Dan Beam, 2016/03/21 17:01:12]

you can't return from a ctor

[calamity, 2016/03/22 04:32:42]

Seems to work.

http://stackoverflow.com/questions/5255777/what-if-i-write-return-statement-i...

Or is this one of those things that's verboten?

+
   // Set up the chrome://site-engagement/ source.
   scoped_ptr<content::WebUIDataSource> source(
       content::WebUIDataSource::Create(chrome::kChromeUISiteEngagementHost));
   source->AddResourcePath("site_engagement.js", IDR_SITE_ENGAGEMENT_JS);
   source->AddResourcePath(
       "chrome/browser/ui/webui/engagement/site_engagement.mojom",
       IDR_SITE_ENGAGEMENT_MOJO_JS);
   source->SetDefaultResource(IDR_SITE_ENGAGEMENT_HTML);
-
-  content::WebUIDataSource::Add(Profile::FromWebUI(web_ui), source.release());
+    content::WebUIDataSource::Add(profile, source.release());
 }
 
 SiteEngagementUI::~SiteEngagementUI() {}
 
 void SiteEngagementUI::BindUIHandler(
     mojo::InterfaceRequest<SiteEngagementUIHandler> request) {
   ui_handler_.reset(new SiteEngagementUIHandlerImpl(
       Profile::FromWebUI(web_ui()), std::move(request)));
 }