[Sync] Split encryption state and logic out of PSS and SBHI.

components/sync/driver/glue/sync_backend_host_core.h

Index: components/sync/driver/glue/sync_backend_host_core.h
diff --git a/components/sync/driver/glue/sync_backend_host_core.h b/components/sync/driver/glue/sync_backend_host_core.h
index c46814bcf591346e911f164f4eb4de64a34b2c77..31b3a1e9ab3791c0c3e62800637fde448121d257 100644
--- a/components/sync/driver/glue/sync_backend_host_core.h
+++ b/components/sync/driver/glue/sync_backend_host_core.h
@@ -35,7 +35,6 @@ class SyncBackendHostImpl;
 class SyncBackendHostCore
     : public base::RefCountedThreadSafe<SyncBackendHostCore>,
       public base::trace_event::MemoryDumpProvider,
-      public SyncEncryptionHandler::Observer,
       public SyncManager::Observer,
       public TypeDebugInfoObserver {
  public:
@@ -61,22 +60,6 @@ class SyncBackendHostCore
   void OnMigrationRequested(ModelTypeSet types) override;
   void OnProtocolEvent(const ProtocolEvent& event) override;
 
-  // SyncEncryptionHandler::Observer implementation.
-  void OnPassphraseRequired(
-      PassphraseRequiredReason reason,
-      const sync_pb::EncryptedData& pending_keys) override;
-  void OnPassphraseAccepted() override;
-  void OnBootstrapTokenUpdated(const std::string& bootstrap_token,
-                               BootstrapTokenType type) override;
-  void OnEncryptedTypesChanged(ModelTypeSet encrypted_types,
-                               bool encrypt_everything) override;
-  void OnEncryptionComplete() override;
-  void OnCryptographerStateChanged(Cryptographer* cryptographer) override;
-  void OnPassphraseTypeChanged(PassphraseType type,
-                               base::Time passphrase_time) override;
-  void OnLocalSetPassphraseEncryption(
-      const SyncEncryptionHandler::NigoriState& nigori_state) override;
-
   // TypeDebugInfoObserver implementation
   void OnCommitCountersUpdated(ModelType type,
                                const CommitCounters& counters) override;
@@ -208,6 +191,7 @@ class SyncBackendHostCore
 
   // Non-null only between calls to DoInitialize() and DoShutdown().
   std::unique_ptr<SyncBackendRegistrar> registrar_;
+  std::unique_ptr<SyncEncryptionHandler::Observer> encryption_observer_proxy_;
 
   // The timer used to periodically call SaveChanges.
   std::unique_ptr<base::RepeatingTimer> save_changes_timer_;