Convert ConnectToApplication to take a params class

mojo/services/tracing/public/cpp/tracing_impl.cc

Index: mojo/services/tracing/public/cpp/tracing_impl.cc
diff --git a/mojo/services/tracing/public/cpp/tracing_impl.cc b/mojo/services/tracing/public/cpp/tracing_impl.cc
index 1cffe036d16ced3362bb767e527b71410ff80148..eed10f28bb36137935572abbc1f324e0927ef23a 100644
--- a/mojo/services/tracing/public/cpp/tracing_impl.cc
+++ b/mojo/services/tracing/public/cpp/tracing_impl.cc
@@ -51,9 +51,7 @@ void TracingImpl::Initialize(ApplicationImpl* app) {
   // up to something like CoreServices to name its own child threads.
   base::PlatformThread::SetName(app->url());
 
-  mojo::URLRequestPtr request(mojo::URLRequest::New());
-  request->url = mojo::String::From("mojo:tracing");
-  connection_ = app->ConnectToApplication(request.Pass());
+  connection_ = app->ConnectToApplication("mojo:tracing");
   connection_->AddService(this);
 
 #ifdef NDEBUG