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

mojo/services/test_service/test_request_tracker_application.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 "mojo/services/test_service/test_request_tracker_application.h"
 
 #include <assert.h>
 #include <utility>
 
 #include "mojo/public/c/system/main.h"
 #include "mojo/services/test_service/test_time_service_impl.h"
 #include "mojo/shell/public/cpp/application_connection.h"
 #include "mojo/shell/public/cpp/application_runner.h"
 
 namespace mojo {
 namespace test {
 
 TestRequestTrackerApplication::TestRequestTrackerApplication()
-    : app_impl_(nullptr) {
-}
+    : shell_(nullptr) {}
+TestRequestTrackerApplication::~TestRequestTrackerApplication() {}
 
-TestRequestTrackerApplication::~TestRequestTrackerApplication() {
-}
-
-void TestRequestTrackerApplication::Initialize(ApplicationImpl* app) {
-  app_impl_ = app;
+void TestRequestTrackerApplication::Initialize(Shell* shell,
+                                               const std::string& url,
+                                               uint32_t id) {
+  shell_ = shell;
 }
 
 bool TestRequestTrackerApplication::AcceptConnection(
     ApplicationConnection* connection) {
   // Every instance of the service and recorder shares the context.
   // Note, this app is single-threaded, so this is thread safe.
   connection->AddService<TestTimeService>(this);
   connection->AddService<TestRequestTracker>(this);
   connection->AddService<TestTrackedRequestService>(this);
   return true;
 }
 
 void TestRequestTrackerApplication::Create(
     ApplicationConnection* connection,
     InterfaceRequest<TestTimeService> request) {
-  new TestTimeServiceImpl(app_impl_, std::move(request));
+  new TestTimeServiceImpl(shell_, std::move(request));
 }
 
 void TestRequestTrackerApplication::Create(
     ApplicationConnection* connection,
     InterfaceRequest<TestRequestTracker> request) {
   new TestRequestTrackerImpl(std::move(request), &context_);
 }
 
 void TestRequestTrackerApplication::Create(
     ApplicationConnection* connection,
     InterfaceRequest<TestTrackedRequestService> request) {
   new TestTrackedRequestServiceImpl(std::move(request), &context_);
 }
 
 }  // namespace test
 }  // namespace mojo
 
 MojoResult MojoMain(MojoHandle shell_handle) {
   mojo::ApplicationRunner runner(
       new mojo::test::TestRequestTrackerApplication);
   return runner.Run(shell_handle);
 }