Make Service own ServiceContext.

components/filesystem/file_system_app.cc

Index: components/filesystem/file_system_app.cc
diff --git a/components/filesystem/file_system_app.cc b/components/filesystem/file_system_app.cc
index fb73c947c7eccdba397bb416fc4ec5aacc850025..a47ffbf1903f0c2de0c803f6966e4bc998532bef 100644
--- a/components/filesystem/file_system_app.cc
+++ b/components/filesystem/file_system_app.cc
@@ -39,10 +39,8 @@ FileSystemApp::FileSystemApp() : lock_table_(new LockTable) {}
 
 FileSystemApp::~FileSystemApp() {}
 
-void FileSystemApp::OnStart(shell::Connector* connector,
-                            const shell::Identity& identity,
-                            uint32_t id) {
-  tracing_.Initialize(connector, identity.name());
+void FileSystemApp::OnStart(const shell::Identity& identity) {
+  tracing_.Initialize(connector(), identity.name());
 }
 
 bool FileSystemApp::OnConnect(shell::Connection* connection) {