[Sync] Add support for automatic enabling of syncing tab favicons.

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>
 
 #include "base/basictypes.h"
 #include "base/callback_forward.h"
 #include "base/file_path.h"
 #include "base/memory/ref_counted.h"
 #include "base/task_runner.h"
 #include "base/threading/thread_checker.h"
 #include "base/time.h"
 #include "sync/internal_api/change_record.h"
 #include "sync/internal_api/configure_reason.h"
 #include "sync/protocol/sync_protocol_error.h"
 #include "sync/syncable/model_type.h"
 #include "sync/util/report_unrecoverable_error_function.h"
 #include "sync/util/unrecoverable_error_handler.h"
 #include "sync/util/weak_handle.h"
 
 namespace browser_sync {
 class Encryptor;
+struct Experiments;
 class ExtensionsActivityMonitor;
 class JsBackend;
 class JsEventHandler;
 class ModelSafeWorkerRegistrar;
 
 namespace sessions {
 class SyncSessionSnapshot;
 }  // namespace sessions
 }  // namespace browser_sync
 
@@ skipping 546 matching lines @@
   void EnableEncryptEverything();
 
   // Returns true if we are currently encrypting all sync data.  May
   // be called on any thread.
   bool EncryptEverythingEnabledForTest() const;
 
   // Gets the set of encrypted types from the cryptographer
   // Note: opens a transaction.  May be called from any thread.
   syncable::ModelTypeSet GetEncryptedDataTypesForTest() const;
 
-  // Reads the nigori node to determine if any experimental types should be
-  // enabled.
+  // Reads the nigori node to determine if any experimental features should
+  // be enabled.
   // Note: opens a transaction.  May be called on any thread.
-  bool ReceivedExperimentalTypes(syncable::ModelTypeSet* to_add) const;
+  bool ReceivedExperiment(browser_sync::Experiments* experiments) const;
 
   // Uses a read-only transaction to determine if the directory being synced has
   // any remaining unsynced items.  May be called on any thread.
   bool HasUnsyncedItems() const;
 
   // Functions used for testing.
 
   void TriggerOnNotificationStateChangeForTest(
       bool notifications_enabled);
 
@@ skipping 27 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_