Make Service own ServiceContext.

components/font_service/font_service_app.cc

Index: components/font_service/font_service_app.cc
diff --git a/components/font_service/font_service_app.cc b/components/font_service/font_service_app.cc
index 2cb77bd00e372ae2bfadd7ea2d54cf94c6372b47..9d586441148364ca5cd921a09666a6ee32985c86 100644
--- a/components/font_service/font_service_app.cc
+++ b/components/font_service/font_service_app.cc
@@ -48,10 +48,8 @@ FontServiceApp::FontServiceApp() {}
 
 FontServiceApp::~FontServiceApp() {}
 
-void FontServiceApp::OnStart(shell::Connector* connector,
-                             const shell::Identity& identity,
-                             uint32_t id) {
-  tracing_.Initialize(connector, identity.name());
+void FontServiceApp::OnStart(const shell::Identity& identity) {
+  tracing_.Initialize(connector(), identity.name());
 }
 
 bool FontServiceApp::OnConnect(shell::Connection* connection) {