Extract shell methods from ApplicationImpl into a base class, and pass this to Initialize() instead.

mojo/shell/fetcher/about_fetcher_unittest.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 "mojo/shell/fetcher/about_fetcher.h"
 
 #include <stddef.h>
 
 #include <utility>
 
@@ skipping 24 matching lines @@
                            public mojom::ContentHandler {
  public:
   TestContentHandler() : response_number_(0) {}
   ~TestContentHandler() override {}
 
   size_t response_number() const { return response_number_; }
   const URLResponse* latest_response() const { return latest_response_.get(); }
 
  private:
   // Overridden from ApplicationDelegate:
-  void Initialize(ApplicationImpl* app) override {}
+  void Initialize(Shell* shell, const std::string& url, uint32_t id) override {}
   bool AcceptConnection(ApplicationConnection* connection) override {
     connection->AddService<mojom::ContentHandler>(this);
     return true;
   }
 
   // Overridden from InterfaceFactory<mojom::ContentHandler>:
   void Create(ApplicationConnection* connection,
               InterfaceRequest<mojom::ContentHandler> request) override {
     bindings_.AddBinding(this, std::move(request));
   }
@@ skipping 117 matching lines @@
   const URLResponse* response = html_content_handler()->latest_response();
   EXPECT_EQ("about:some_unrecognized_url", response->url);
   EXPECT_EQ(404u, response->status_code);
   EXPECT_EQ("text/html", response->mime_type);
   EXPECT_FALSE(response->body.is_valid());
 }
 
 }  // namespace
 }  // namespace shell
 }  // namespace mojo