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

components/sync/engine/sync_encryption_handler.h

Index: components/sync/engine/sync_encryption_handler.h
diff --git a/components/sync/engine/sync_encryption_handler.h b/components/sync/engine/sync_encryption_handler.h
index db6564532518daa5b645617f2d7d3634b08ed02a..617aa77fbffaaf4638645a0b511a90dcd77c5f98 100644
--- a/components/sync/engine/sync_encryption_handler.h
+++ b/components/sync/engine/sync_encryption_handler.h
@@ -48,6 +48,7 @@ class SyncEncryptionHandler {
   class Observer {
    public:
     Observer();
+    virtual ~Observer();
 
     // Called when user interaction is required to obtain a valid passphrase.
     // - If the passphrase is required for encryption, |reason| will be
@@ -116,9 +117,6 @@ class SyncEncryptionHandler {
     // RestoredNigori method.
     virtual void OnLocalSetPassphraseEncryption(
         const NigoriState& nigori_state) = 0;
-
-   protected:
-    virtual ~Observer();
   };
 
   class NigoriState {