Changing SessionService to have a BaseSessionService, not being one.

chrome/browser/sessions/session_service.h

Index: chrome/browser/sessions/session_service.h
diff --git a/chrome/browser/sessions/session_service.h b/chrome/browser/sessions/session_service.h
index 44a2ff5c6b06fbf5eb8fb9fb1a8afe386f9e41aa..b0f8e9631355a06d5394711d513999f99bc48f3a 100644
--- a/chrome/browser/sessions/session_service.h
+++ b/chrome/browser/sessions/session_service.h
@@ -15,7 +15,7 @@
 #include "base/task/cancelable_task_tracker.h"
 #include "base/time/time.h"
 #include "chrome/browser/defaults.h"
-#include "chrome/browser/sessions/base_session_service.h"
+#include "chrome/browser/sessions/base_session_service_delegate_impl.h"
 #include "chrome/browser/sessions/session_service_commands.h"
 #include "chrome/browser/sessions/session_service_utils.h"
 #include "chrome/browser/ui/browser.h"
@@ -56,7 +56,7 @@ class WebContents;
 // flushed to |SessionBackend| and written to a file. Every so often
 // |SessionService| rebuilds the contents of the file from the open state of the
 // browser.
-class SessionService : public BaseSessionService,
+class SessionService : public BaseSessionServiceDelegateImpl,
                        public KeyedService,
                        public content::NotificationObserver,
                        public chrome::BrowserListObserver {
@@ -100,6 +100,9 @@ class SessionService : public BaseSessionService,
   // browsers are running.
   void MoveCurrentSessionToLastSession();
 
+  // Deletes the last session.
+  void DeleteLastSession();
+
   // Associates a tab with a window.
   void SetTabWindow(const SessionID& window_id,
                     const SessionID& tab_id);
@@ -207,9 +210,11 @@ class SessionService : public BaseSessionService,
       const SessionCallback& callback,
       base::CancelableTaskTracker* tracker);
 
-  // Overridden from BaseSessionService because we want some UMA reporting on
-  // session update activities.
-  void Save() override;
+  // BaseSessionServiceDelegateImpl:
+  void OnSavedCommands() override;
+
+  // Unit test accessors.
+  BaseSessionService* GetBaseSessionServiceForTest();
 
  private:
   // Allow tests to access our innards for testing purposes.
@@ -229,10 +234,6 @@ class SessionService : public BaseSessionService,
   // Removes unrestorable windows from the previous windows list.
   void RemoveUnusedRestoreWindows(std::vector<SessionWindow*>* window_list);
 
-  // Returns true if we have scheduled any commands, or any scheduled commands
-  // have been saved.
-  bool processed_any_commands();
-
   // Implementation of RestoreIfNecessary. If |browser| is non-null and we need
   // to restore, the tabs are added to it, otherwise a new browser is created.
   bool RestoreIfNecessary(const std::vector<GURL>& urls_to_open,
@@ -287,7 +288,7 @@ class SessionService : public BaseSessionService,
   void ScheduleResetCommands();
 
   // Schedules the specified command.
-  void ScheduleCommand(scoped_ptr<SessionCommand> command) override;
+  void ScheduleCommand(scoped_ptr<SessionCommand> command);
 
   // Converts all pending tab/window closes to commands and schedules them.
   void CommitPendingCloses();
@@ -330,6 +331,9 @@ class SessionService : public BaseSessionService,
   // The profile. This may be null during testing.
   Profile* profile_;
 
+  // The owned BaseSessionService.
+  scoped_ptr<BaseSessionService> base_session_service_;
+
   content::NotificationRegistrar registrar_;
 
   // Maps from session tab id to the range of navigation entries that has