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

chrome/browser/chromeos/file_system_provider/service_factory.h

Index: chrome/browser/chromeos/file_system_provider/service_factory.h
diff --git a/chrome/browser/chromeos/file_system_provider/service_factory.h b/chrome/browser/chromeos/file_system_provider/service_factory.h
index 2aad0ddb63f87602c0845c604c5fb268a556c40d..bb7cde19b832c4c9500132b921d7eefbc0320d73 100644
--- a/chrome/browser/chromeos/file_system_provider/service_factory.h
+++ b/chrome/browser/chromeos/file_system_provider/service_factory.h
@@ -21,7 +21,14 @@ 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: