[fsp] Introduce chrome://fsp-internals for logging and debugging.

chrome/browser/chromeos/file_system_provider/service_factory.h

 // Copyright 2014 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 CHROME_BROWSER_CHROMEOS_FILE_SYSTEM_PROVIDER_SERVICE_FACTORY_H_
 #define CHROME_BROWSER_CHROMEOS_FILE_SYSTEM_PROVIDER_SERVICE_FACTORY_H_
 
 #include <map>
 #include <string>
 #include <vector>
 
 #include "base/memory/singleton.h"
 #include "components/keyed_service/content/browser_context_keyed_service_factory.h"
 #include "content/public/browser/browser_context.h"
 
 namespace chromeos {
 namespace file_system_provider {
 
 class Service;
 
 // Creates services per profile.
 class ServiceFactory : public BrowserContextKeyedServiceFactory {
  public:
+  // Returns a service instance singleton, after creating it (if necessary).
   static Service* Get(content::BrowserContext* context);
+
+  // Returns a service instance for the context if exists. Otherwise, returns
+  // NULL.
+  static Service* FindExisting(content::BrowserContext* context);
+
+  // Gets a singleton instance of the factory.
   static ServiceFactory* GetInstance();
 
  private:
   friend struct DefaultSingletonTraits<ServiceFactory>;
 
   ServiceFactory();
   virtual ~ServiceFactory();
 
   // BrowserContextKeyedServiceFactory overrides:
   virtual KeyedService* BuildServiceInstanceFor(
       content::BrowserContext* profile) const OVERRIDE;
   virtual bool ServiceIsCreatedWithBrowserContext() const OVERRIDE;
 
   DISALLOW_COPY_AND_ASSIGN(ServiceFactory);
 };
 
 }  // namespace file_system_provider
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_FILE_SYSTEM_PROVIDER_SERVICE_FACTORY_H_