Revert of [Service Manager] Get rid of dynamic service discovery

services/service_manager/standalone/context.h

Index: services/service_manager/standalone/context.h
diff --git a/services/service_manager/standalone/context.h b/services/service_manager/standalone/context.h
index a10e572ebd3d0e3efda0d5bd0199bb1412f1cce6..e9d9aa6e4666ae2437c9978bee99f1776f9146d9 100644
--- a/services/service_manager/standalone/context.h
+++ b/services/service_manager/standalone/context.h
@@ -7,16 +7,19 @@
 
 #include <memory>
 
+#include "base/callback_forward.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
+#include "base/threading/thread.h"
 #include "base/time/time.h"
 #include "base/values.h"
 #include "services/service_manager/runner/host/service_process_launcher.h"
+#include "services/service_manager/service_manager.h"
 #include "services/service_manager/standalone/tracer.h"
 #include "services/tracing/public/cpp/provider.h"
 
 namespace base {
-class Value;
+class SingleThreadTaskRunner;
 }
 
 namespace catalog {
@@ -25,16 +28,33 @@
 
 namespace service_manager {
 
-class ServiceManager;
-
 constexpr size_t kThreadPoolMaxThreads = 3;
 
 // The "global" context for the service manager's main process.
 class Context {
  public:
-  Context(ServiceProcessLauncher::Delegate* launcher_delegate,
-          std::unique_ptr<base::Value> catalog_content);
+  struct InitParams {
+    InitParams();
+    ~InitParams();
+
+    ServiceProcessLauncher::Delegate*
+        service_process_launcher_delegate = nullptr;
+    std::unique_ptr<base::Value> static_catalog;
+    // If true the edk is initialized.
+    bool init_edk = true;
+  };
+
+  Context();
   ~Context();
+
+  static void EnsureEmbedderIsInitialized();
+
+  // This must be called with a message loop set up for the current thread,
+  // which must remain alive until after Shutdown() is called.
+  void Init(std::unique_ptr<InitParams> init_params);
+
+  // If Init() was called and succeeded, this must be called before destruction.
+  void Shutdown();
 
   // Run the application specified on the command line.
   void RunCommandLineApplication();
@@ -42,16 +62,23 @@
   ServiceManager* service_manager() { return service_manager_.get(); }
 
  private:
+  void OnShutdownComplete();
+
   // Runs the app specified by |name|.
   void Run(const std::string& name);
 
+  scoped_refptr<base::SingleThreadTaskRunner> service_manager_runner_;
+  std::unique_ptr<base::Thread> io_thread_;
   scoped_refptr<base::SequencedWorkerPool> blocking_pool_;
 
+  // Ensure this is destructed before task_runners_ since it owns a message pipe
+  // that needs the IO thread to destruct cleanly.
   Tracer tracer_;
   tracing::Provider provider_;
   std::unique_ptr<catalog::Catalog> catalog_;
   std::unique_ptr<ServiceManager> service_manager_;
   base::Time main_entry_time_;
+  bool init_edk_ = false;
 
   DISALLOW_COPY_AND_ASSIGN(Context);
 };