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

mojo/services/tracing/public/cpp/tracing_impl.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/tracing/public/cpp/tracing_impl.h"
 
 #include <utility>
 
 #include "base/lazy_instance.h"
 #include "base/synchronization/lock.h"
 #include "base/threading/platform_thread.h"
 #include "base/trace_event/trace_event_impl.h"
-#include "mojo/shell/public/cpp/application_impl.h"
+#include "mojo/shell/public/cpp/shell.h"
 
 #ifdef NDEBUG
 #include "base/command_line.h"
 #include "mojo/services/tracing/public/cpp/switches.h"
 #endif
 
 namespace mojo {
 namespace {
 
 // Controls access to |g_tracing_singleton_created|, which can be accessed from
@@ skipping 10 matching lines @@
 bool g_tracing_singleton_created = false;
 
 }
 
 TracingImpl::TracingImpl() {
 }
 
 TracingImpl::~TracingImpl() {
 }
 
-void TracingImpl::Initialize(ApplicationImpl* app) {
+void TracingImpl::Initialize(Shell* shell, const std::string& url) {
   {
     base::AutoLock lock(g_singleton_lock.Get());
     if (g_tracing_singleton_created)
       return;
     g_tracing_singleton_created = true;
   }
 
   // This will only set the name for the first app in a loaded mojo file. It's
   // up to something like CoreServices to name its own child threads.
-  base::PlatformThread::SetName(app->url());
+  base::PlatformThread::SetName(url);
 
-  connection_ = app->ConnectToApplication("mojo:tracing");
+  connection_ = shell->ConnectToApplication("mojo:tracing");
   connection_->AddService(this);
 
 #ifdef NDEBUG
   if (base::CommandLine::ForCurrentProcess()->HasSwitch(
           tracing::kEarlyTracing)) {
     provider_impl_.ForceEnableTracing();
   }
 #else
   provider_impl_.ForceEnableTracing();
 #endif
 }
 
 void TracingImpl::Create(ApplicationConnection* connection,
                          InterfaceRequest<tracing::TraceProvider> request) {
   provider_impl_.Bind(std::move(request));
 }
 
 }  // namespace mojo