Extract InstallVerifier from ExtensionSystem.

chrome/browser/extensions/api/developer_private/developer_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/developer_private/developer_private_api.h"
 
 #include "base/bind.h"
 #include "base/files/file_util.h"
 #include "base/lazy_instance.h"
 #include "base/metrics/histogram_macros.h"
@@ skipping 134 matching lines @@
         ((prefs->GetDisableReasons(extension->id()) &
              Extension::DISABLE_NOT_VERIFIED) != 0)) {
       should_do_verification_check = true;
       break;
     }
   }
 
   UMA_HISTOGRAM_BOOLEAN("ExtensionSettings.ShouldDoVerificationCheck",
                         should_do_verification_check);
   if (should_do_verification_check)
-    ExtensionSystem::Get(context)->install_verifier()->VerifyAllExtensions();
+    InstallVerifier::Get(context)->VerifyAllExtensions();
 }
 
 }  // namespace
 
 namespace ChoosePath = api::developer_private::ChoosePath;
 namespace GetItemsInfo = api::developer_private::GetItemsInfo;
 namespace PackDirectory = api::developer_private::PackDirectory;
 namespace Reload = api::developer_private::Reload;
 
 static base::LazyInstance<BrowserContextKeyedAPIFactory<DeveloperPrivateAPI> >
@@ skipping 1177 matching lines @@
   // We explicitly show manifest.json in order to work around an issue in OSX
   // where opening the directory doesn't focus the Finder.
   platform_util::ShowItemInFolder(GetProfile(),
                                   extension->path().Append(kManifestFilename));
   return RespondNow(NoArguments());
 }
 
 }  // namespace api
 
 }  // namespace extensions