Extract abstract base to API directory for ProfileSyncService.

chrome/browser/api/sync/profile_sync_service_observer.h

Index: chrome/browser/api/sync/profile_sync_service_observer.h
diff --git a/chrome/browser/sync/profile_sync_service_observer.h b/chrome/browser/api/sync/profile_sync_service_observer.h
similarity index 80%
rename from chrome/browser/sync/profile_sync_service_observer.h
rename to chrome/browser/api/sync/profile_sync_service_observer.h
index de8c997ed50c1ea53f713e98a47978a4dad1b093..8e1d4f92963063ce1f0716acf98a696bb15ee761 100644
--- a/chrome/browser/sync/profile_sync_service_observer.h
+++ b/chrome/browser/api/sync/profile_sync_service_observer.h
@@ -2,8 +2,8 @@
 // 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_
+#ifndef CHROME_BROWSER_API_SYNC_PROFILE_SYNC_SERVICE_OBSERVER_H_
+#define CHROME_BROWSER_API_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.
@@ -20,4 +20,4 @@ class ProfileSyncServiceObserver {
   virtual ~ProfileSyncServiceObserver() { }
 };
 
-#endif  // CHROME_BROWSER_SYNC_PROFILE_SYNC_SERVICE_OBSERVER_H_
+#endif  // CHROME_BROWSER_API_SYNC_PROFILE_SYNC_SERVICE_OBSERVER_H_