[Sync] Convert SyncSessionSnapshot to a copy-able class.

sync/internal_api/sync_manager.h

 // 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.
 
 #ifndef SYNC_INTERNAL_API_SYNC_MANAGER_H_
 #define SYNC_INTERNAL_API_SYNC_MANAGER_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 13 matching lines @@
 #include "sync/util/weak_handle.h"
 
 namespace browser_sync {
 class Encryptor;
 class ExtensionsActivityMonitor;
 class JsBackend;
 class JsEventHandler;
 class ModelSafeWorkerRegistrar;
 
 namespace sessions {
-struct SyncSessionSnapshot;
+class SyncSessionSnapshot;
 }  // namespace sessions
 }  // namespace browser_sync
 
 namespace sync_notifier {
 class SyncNotifier;
 }  // namespace sync_notifier
 
 namespace sync_pb {
 class EncryptedData;
 }  // namespace sync_pb
@@ skipping 200 matching lines @@
 
   // An interface the embedding application implements to receive
   // notifications from the SyncManager.  Register an observer via
   // SyncManager::AddObserver.  All methods are called only on the
   // sync thread.
   class Observer {
    public:
     // A round-trip sync-cycle took place and the syncer has resolved any
     // conflicts that may have arisen.
     virtual void OnSyncCycleCompleted(
-        const browser_sync::sessions::SyncSessionSnapshot* snapshot) = 0;
+        const browser_sync::sessions::SyncSessionSnapshot& snapshot) = 0;
 
     // Called when the status of the connection to the sync server has
     // changed.
     virtual void OnConnectionStatusChange(ConnectionStatus status) = 0;
 
     // Called when a new auth token is provided by the sync server.
     virtual void OnUpdatedToken(const std::string& token) = 0;
 
     // Called when user interaction is required to obtain a valid passphrase.
     // - If the passphrase is required for encryption, |reason| will be
@@ skipping 369 matching lines @@
     sync_api::UserShare* share);
 
 const char* ConnectionStatusToString(ConnectionStatus status);
 
 // Returns the string representation of a PassphraseRequiredReason value.
 const char* PassphraseRequiredReasonToString(PassphraseRequiredReason reason);
 
 }  // namespace sync_api
 
 #endif  // SYNC_INTERNAL_API_SYNC_MANAGER_H_