Fixes race in Shell

services/catalog/catalog.cc

Index: services/catalog/catalog.cc
diff --git a/services/catalog/catalog.cc b/services/catalog/catalog.cc
index 235c79e2783e643c9b033df920f9e36226ffa8fb..35f5d706a67029e8e4f1d52c8ba0f22dfb5ff18e 100644
--- a/services/catalog/catalog.cc
+++ b/services/catalog/catalog.cc
@@ -14,30 +14,43 @@
 
 namespace catalog {
 
-Catalog::Catalog(base::TaskRunner* file_task_runner,
+Catalog::Catalog(base::SequencedWorkerPool* worker_pool,
                  std::unique_ptr<Store> store,
                  ManifestProvider* manifest_provider)
-    : file_task_runner_(file_task_runner),
-      store_(std::move(store)),
-      weak_factory_(this) {
+    : Catalog(std::move(store)) {
+  system_reader_.reset(new Reader(worker_pool, manifest_provider));
+  ScanSystemPackageDir();
+}
+
+Catalog::Catalog(base::SingleThreadTaskRunner* task_runner,
+                 std::unique_ptr<Store> store,
+                 ManifestProvider* manifest_provider)
+    : Catalog(std::move(store)) {
+  system_reader_.reset(new Reader(task_runner, manifest_provider));
+  ScanSystemPackageDir();
+}
+
+Catalog::~Catalog() {}
+
+shell::mojom::ShellClientPtr Catalog::TakeShellClient() {
+  return std::move(shell_client_);
+}
+
+Catalog::Catalog(std::unique_ptr<Store> store)
+    : store_(std::move(store)), weak_factory_(this) {
   shell::mojom::ShellClientRequest request = GetProxy(&shell_client_);
   shell_connection_.reset(new shell::ShellConnection(this, std::move(request)));
+}
 
+void Catalog::ScanSystemPackageDir() {
   base::FilePath system_package_dir;
   PathService::Get(base::DIR_MODULE, &system_package_dir);
   system_package_dir = system_package_dir.AppendASCII(kMojoApplicationsDirName);
-  system_reader_.reset(new Reader(file_task_runner, manifest_provider));
   system_reader_->Read(system_package_dir, &system_cache_,
                        base::Bind(&Catalog::SystemPackageDirScanned,
                                   weak_factory_.GetWeakPtr()));
 }
 
-Catalog::~Catalog() {}
-
-shell::mojom::ShellClientPtr Catalog::TakeShellClient() {
-  return std::move(shell_client_);
-}
-
 bool Catalog::AcceptConnection(shell::Connection* connection) {
   connection->AddInterface<mojom::Catalog>(this);
   connection->AddInterface<shell::mojom::ShellResolver>(this);