[Sync] Implement MemoryDumpProvider.

components/sync/syncable/syncable_id.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 COMPONENTS_SYNC_SYNCABLE_SYNCABLE_ID_H_
 #define COMPONENTS_SYNC_SYNCABLE_SYNCABLE_ID_H_
 
 #include <iosfwd>
 #include <limits>
 #include <memory>
 #include <sstream>
 #include <string>
 
 #include "base/containers/hash_tables.h"
+#include "base/trace_event/memory_usage_estimator.h"
 
 namespace base {
 class StringValue;
 }  // namespace base
 
 namespace sql {
 class Statement;
 }  // namespace sql
 
 namespace syncer {
@@ skipping 65 matching lines @@
  private:
   friend std::unique_ptr<EntryKernel> UnpackEntry(sql::Statement* statement,
                                                   int* total_created_entries);
   friend void BindFields(const EntryKernel& entry, sql::Statement* statement);
   friend std::ostream& operator<<(std::ostream& out, const Id& id);
   friend class SyncableIdTest;
 
   std::string s_;
 };
 
+inline size_t EstimateMemoryUsage(const Id& id) {
+  return base::trace_event::EstimateMemoryUsage(id.value());
+}
+
 }  // namespace syncable
 }  // namespace syncer
 
 #endif  // COMPONENTS_SYNC_SYNCABLE_SYNCABLE_ID_H_