Fix WebApkInstallService::IsInstallInProgress() crash.

chrome/browser/android/webapk/webapk_install_service_factory.cc

 // Copyright 2016 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/android/webapk/webapk_install_service_factory.h"
 
 #include "chrome/browser/android/webapk/webapk_install_service.h"
 #include "components/keyed_service/content/browser_context_dependency_manager.h"
 
 // static
@@ skipping 12 matching lines @@
     : BrowserContextKeyedServiceFactory(
           "WebApkInstallService",
           BrowserContextDependencyManager::GetInstance()) {}
 
 WebApkInstallServiceFactory::~WebApkInstallServiceFactory() {}
 
 KeyedService* WebApkInstallServiceFactory::BuildServiceInstanceFor(
     content::BrowserContext* context) const {
   return new WebApkInstallService(context);
 }
+
+content::BrowserContext* WebApkInstallServiceFactory::GetBrowserContextToUse(
+    content::BrowserContext* context) const {
+  // Returns the original (possibly off-the-record) browser context so that a
+  // separate instance of the WebApkInstallerService is used in incognito mode.
+  // The base class's implementation returns nullptr.

[pkotwicz, 2017/01/12 15:37:42]

Are you sure that you want incognito and non-incognito to use different
WebApkInstallService instances? This means that it would be possible to start an
install from an incognito tab while an install started from a non incognito tab
is in progress.

I think that you are supposed to return one of
chrome/browser/profiles/incognito_helpers.h

[Xi Han, 2017/01/12 15:50:36]

Makes sense. 

[pkotwicz, 2017/01/12 15:55:40]

I think that you should be using GetBrowserContextRedirectedInIncognito() for
the reason described in my previous comment

[Xi Han, 2017/01/12 16:25:23]

Oops, choose the wrong one.

+  return context;
+}