Extract abstract base to API directory for ProfileSyncService.

chrome/browser/sync/profile_sync_service_observer.h

Index: chrome/browser/sync/profile_sync_service_observer.h
diff --git a/chrome/browser/sync/profile_sync_service_observer.h b/chrome/browser/sync/profile_sync_service_observer.h
deleted file mode 100644
index de8c997ed50c1ea53f713e98a47978a4dad1b093..0000000000000000000000000000000000000000
--- a/chrome/browser/sync/profile_sync_service_observer.h
+++ /dev/null
@@ -1,23 +0,0 @@
-// 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 CHROME_BROWSER_SYNC_PROFILE_SYNC_SERVICE_OBSERVER_H_
-#define CHROME_BROWSER_SYNC_PROFILE_SYNC_SERVICE_OBSERVER_H_
-
-// Various UI components such as the New Tab page can be driven by observing
-// the ProfileSyncService through this interface.
-class ProfileSyncServiceObserver {
- public:
-  // When one of the following events occurs, OnStateChanged() is called.
-  // Observers should query the service to determine what happened.
-  // - We initialized successfully.
-  // - There was an authentication error and the user needs to reauthenticate.
-  // - The sync servers are unavailable at this time.
-  // - Credentials are now in flight for authentication.
-  virtual void OnStateChanged() = 0;
- protected:
-  virtual ~ProfileSyncServiceObserver() { }
-};
-
-#endif  // CHROME_BROWSER_SYNC_PROFILE_SYNC_SERVICE_OBSERVER_H_