[sync] Isolate FOREIGN_SESSION_UPDATED notification in ProfileSyncService

chrome/browser/android/foreign_session_helper.h

Index: chrome/browser/android/foreign_session_helper.h
diff --git a/chrome/browser/android/foreign_session_helper.h b/chrome/browser/android/foreign_session_helper.h
index 2eb47bc23d4178ba9b957ba1f48595a5f92221f3..5c4a9bc21d6e48e0b05d732af1de98028c039e06 100644
--- a/chrome/browser/android/foreign_session_helper.h
+++ b/chrome/browser/android/foreign_session_helper.h
@@ -11,8 +11,6 @@
 #include "base/scoped_observer.h"
 #include "chrome/browser/profiles/profile.h"
 #include "components/sync_driver/sync_service_observer.h"
-#include "content/public/browser/notification_observer.h"
-#include "content/public/browser/notification_registrar.h"
 
 using base::android::ScopedJavaLocalRef;
 
@@ -26,8 +24,7 @@ namespace sync_driver {
 class SyncService;
 }  // namespace sync_driver
 
-class ForeignSessionHelper : public content::NotificationObserver,
-                             public sync_driver::SyncServiceObserver {
+class ForeignSessionHelper : public sync_driver::SyncServiceObserver {
  public:
   explicit ForeignSessionHelper(Profile* profile);
   void Destroy(JNIEnv* env, jobject obj);
@@ -43,14 +40,10 @@ class ForeignSessionHelper : public content::NotificationObserver,
                                  jint disposition);
   void DeleteForeignSession(JNIEnv* env, jobject obj, jstring session_tag);
 
-  // NotificationObserver implemenation
-  void Observe(int type,
-               const content::NotificationSource& source,
-               const content::NotificationDetails& details) override;
-
   // sync_driver::SyncServiceObserver implementation
   void OnStateChanged() override {}
   void OnSyncConfigurationCompleted() override;
+  void OnForeignSessionUpdated() override;
 
   static bool RegisterForeignSessionHelper(JNIEnv* env);
 
@@ -62,7 +55,6 @@ class ForeignSessionHelper : public content::NotificationObserver,
 
   Profile* profile_;  // weak
   base::android::ScopedJavaGlobalRef<jobject> callback_;
-  content::NotificationRegistrar registrar_;
   ScopedObserver<sync_driver::SyncService, sync_driver::SyncServiceObserver>
       scoped_observer_;