Revert of Change the update_client task runner behavior to continue on shutdown.

extensions/browser/updater/update_service_unittest.cc

 // Copyright 2014 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 <vector>
 
 #include "base/files/file_util.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/run_loop.h"
 #include "base/values.h"
@@ skipping 28 matching lines @@
                const CompletionCallback& completion_callback) override {}
   void Update(const std::vector<std::string>& ids,
               const CrxDataCallback& crx_data_callback,
               const CompletionCallback& completion_callback) override;
   bool GetCrxUpdateState(
       const std::string& id,
       update_client::CrxUpdateItem* update_item) const override {
     return false;
   }
   bool IsUpdating(const std::string& id) const override { return false; }
-  void Stop() override {}
 
  protected:
   friend class base::RefCounted<FakeUpdateClient>;
   ~FakeUpdateClient() override {}
 
   std::vector<update_client::CrxComponent> data_;
 };
 
 FakeUpdateClient::FakeUpdateClient() {}
 
@@ skipping 180 matching lines @@
   std::vector<FakeExtensionSystem::InstallUpdateRequest>* requests =
       extension_system()->install_requests();
   ASSERT_EQ(1u, requests->size());
   EXPECT_EQ(requests->at(0).extension_id, extension1->id());
   EXPECT_NE(requests->at(0).temp_dir.value(), new_version_dir.path().value());
 }
 
 }  // namespace
 
 }  // namespace extensions