[Sync] Add support for loading, updating and querying delete journals in

sync/syncable/entry_kernel.h

 // Copyright 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_SYNCABLE_ENTRY_KERNEL_H_
 #define SYNC_SYNCABLE_ENTRY_KERNEL_H_
 
+#include <set>
+
 #include "base/time.h"
 #include "base/values.h"
 #include "sync/base/sync_export.h"
 #include "sync/internal_api/public/base/model_type.h"
 #include "sync/internal_api/public/base/node_ordinal.h"
 #include "sync/internal_api/public/util/immutable.h"
 #include "sync/protocol/sync.pb.h"
 #include "sync/syncable/metahandle_set.h"
 #include "sync/syncable/syncable_id.h"
 #include "sync/util/time.h"
@@ skipping 298 matching lines @@
   // Note: |cryptographer| is an optional parameter for use in decrypting
   // encrypted specifics. If it is NULL or the specifics are not decryptsble,
   // they will be serialized as empty proto's.
   base::DictionaryValue* ToValue(Cryptographer* cryptographer) const;
 
  private:
   // Tracks whether this entry needs to be saved to the database.
   bool dirty_;
 };
 
+class EntryKernelLessByMetaHandle {
+ public:
+  inline bool operator()(const EntryKernel* a,
+                         const EntryKernel* b) const {
+    return a->ref(META_HANDLE) < b->ref(META_HANDLE);
+  }
+};
+
+typedef std::set<const EntryKernel*, EntryKernelLessByMetaHandle>
+    EntryKernelSet;
+
 struct EntryKernelMutation {
   EntryKernel original, mutated;
 };
 
 typedef std::map<int64, EntryKernelMutation> EntryKernelMutationMap;
 
 typedef Immutable<EntryKernelMutationMap> ImmutableEntryKernelMutationMap;
 
 // Caller owns the return value.
 base::DictionaryValue* EntryKernelMutationToValue(
     const EntryKernelMutation& mutation);
 
 // Caller owns the return value.
 base::ListValue* EntryKernelMutationMapToValue(
     const EntryKernelMutationMap& mutations);
 
 }  // namespace syncable
 }  // namespace syncer
 
 #endif // SYNC_SYNCABLE_ENTRY_KERNEL_H_