[Sync] Implement keystore migration support.

sync/engine/conflict_resolver.cc

 // 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.
 
 #include "sync/engine/conflict_resolver.h"
 
 #include <algorithm>
 #include <list>
 #include <map>
 #include <set>
@@ skipping 239 matching lines @@
       //   default encryption key marked as an implicit passphrase.
       // This works fine except for the case where we had locally set an
       // explicit passphrase. In that case the nigori node will have the default
       // key based on the local explicit passphassphrase, but will not have it
       // marked as explicit. To fix this we'd have to track whether we have a
       // explicit passphrase or not separate from the nigori, which would
       // introduce even more complexity, so we leave it up to the user to
       // reset that passphrase as an explicit one via settings. The goal here
       // is to ensure both sets of encryption keys are preserved.
       if (cryptographer->is_ready()) {
-        cryptographer->GetKeys(server_nigori->mutable_encrypted());
-        server_nigori->set_using_explicit_passphrase(
-            entry.Get(syncable::SPECIFICS).nigori().
-                using_explicit_passphrase());
+        cryptographer->GetKeys(server_nigori->mutable_encryption_keybag());
+        server_nigori->set_frozen_keybag(
+            entry.Get(syncable::SPECIFICS).nigori().frozen_keybag());
+        // TODO(zea): tackle migration-induced conflicts here.
       }
       // We deliberately leave the server's device information. This client will
       // add its own device information on restart.
       entry.Put(syncable::SPECIFICS, specifics);
       DVLOG(1) << "Resolving simple conflict, merging nigori nodes: " << entry;
       status->increment_num_server_overwrites();
       OverwriteServerChanges(trans, &entry);
       UMA_HISTOGRAM_ENUMERATION("Sync.ResolveSimpleConflict",
                                 NIGORI_MERGE,
                                 CONFLICT_RESOLUTION_SIZE);
@@ skipping 138 matching lines @@
           forward_progress = true;
           break;
       }
       processed_items.insert(id);
     }
   }
   return forward_progress;
 }
 
 }  // namespace syncer