chromeos: Make CrosDBusService not be a singleton.

chromeos/dbus/services/cros_dbus_service.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROMEOS_DBUS_SERVICES_CROS_DBUS_SERVICE_H_
 #define CHROMEOS_DBUS_SERVICES_CROS_DBUS_SERVICE_H_
 
 #include <memory>
 #include <vector>
 
+#include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/threading/platform_thread.h"
 #include "chromeos/chromeos_export.h"
 
 namespace dbus {
 class Bus;
 class ExportedObject;
+class ObjectPath;
 }
 
 namespace chromeos {
 
-// CrosDBusService is used to run a D-Bus service inside Chrome for Chrome
-// OS. The service will be registered as follows:
-//
-// Service name: org.chromium.LibCrosService (kLibCrosServiceName)
-// Object path: chromium/LibCrosService (kLibCrosServicePath)
-//
-// For historical reasons, the rather irrelevant name "LibCrosService" is
-// used in the D-Bus constants such as the service name.
-//
-// CrosDBusService exports D-Bus methods through service provider classes
-// that implement CrosDBusService::ServiceProviderInterface.
-
+// CrosDBusService is used to run a D-Bus service inside Chrome for Chrome OS.
+// It exports D-Bus methods through service provider classes that implement
+// CrosDBusService::ServiceProviderInterface.

[James Cook, 2017/02/15 01:53:34]

nit: I would include something in this comment about the legacy / weirdly-named
LibCrosService. It's an important part of the history. Alternately, I would
include examples of the services it will be used to provide.

[Daniel Erat, 2017/02/15 16:57:00]

i'm fine with adding more details like this to the place where the
LibCrosService instance is instantiated in chrome_browser_main_chromeos.cc, but
don't think the history belongs here.

 class CHROMEOS_EXPORT CrosDBusService {
  public:
   // CrosDBusService consists of service providers that implement this
   // interface.
   class ServiceProviderInterface {
    public:
     // Starts the service provider. |exported_object| is used to export
     // D-Bus methods.
     virtual void Start(
         scoped_refptr<dbus::ExportedObject> exported_object) = 0;
 
     virtual ~ServiceProviderInterface();
   };
 
   using ServiceProviderList =
       std::vector<std::unique_ptr<ServiceProviderInterface>>;
 
-  // Initializes the global instance.
-  static void Initialize(ServiceProviderList service_providers);
-  // Destroys the global instance.
-  static void Shutdown();
+  // Creates, starts, and returns a new instance owning |service_name| and
+  // exporting |service_providers|'s methods on |object_path|. Static so a stub
+  // implementation can be used when not running on a device.
+  static std::unique_ptr<CrosDBusService> Create(
+      const std::string& service_name,
+      const dbus::ObjectPath& object_path,
+      ServiceProviderList service_providers);
+
+  virtual ~CrosDBusService();
 
  protected:
-  virtual ~CrosDBusService();
+  CrosDBusService();
 
  private:
   friend class CrosDBusServiceTest;
 
-  // Initializes the global instance for testing.
-  static void InitializeForTesting(dbus::Bus* bus,
-                                   ServiceProviderList service_providers);
+  // Creates, starts, and returns a real implementation of CrosDBusService that
+  // uses |bus|. Called by Create(), but can also be called directly by tests
+  // that need a non-stub implementation even when not running on a device.
+  static std::unique_ptr<CrosDBusService> CreateRealImpl(
+      dbus::Bus* bus,
+      const std::string& service_name,
+      const dbus::ObjectPath& object_path,
+      ServiceProviderList service_providers);
+
+  DISALLOW_COPY_AND_ASSIGN(CrosDBusService);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROMEOS_DBUS_SERVICES_CROS_DBUS_SERVICE_H_