Reland: [Sync] Record sync memory usage in histogram broken by datatypes

components/sync/model/model_type_debug_info.h

 // Copyright 2016 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_MODEL_MODEL_TYPE_DEBUG_INFO_H_
 #define COMPONENTS_SYNC_MODEL_MODEL_TYPE_DEBUG_INFO_H_
 
 #include <memory>
 
 #include "base/callback.h"
@@ skipping 17 matching lines @@
                                 std::unique_ptr<base::ListValue>)>& callback,
       ModelTypeSyncBridge* bridge);
 
   // Returns StatusCounters for the type to |callback|.
   // Used for updating data type counters in chrome://sync-internals.
   static void GetStatusCounters(
       const base::Callback<void(const ModelType, const StatusCounters&)>&
           callback,
       ModelTypeSyncBridge* bridge);
 
+  // Queries |bridge| for estimate of memory usage and records it in a
+  // histogram.
+  static void RecordMemoryUsageHistogram(ModelTypeSyncBridge* bridge);
+
  private:
   ModelTypeDebugInfo();
 
   // This is callback function for ModelTypeSyncBridge::GetAllData. This
   // function will merge real data from |batch| with metadata extracted from
   // the |processor|, then pass it all to |callback|.
   static void MergeDataWithMetadata(
       SharedModelTypeProcessor* processor,
       const base::Callback<void(const ModelType,
                                 std::unique_ptr<base::ListValue>)>& callback,
       std::unique_ptr<DataBatch> batch);
 };
 
 }  // namespace syncer
 
 #endif  // COMPONENTS_SYNC_MODEL_MODEL_TYPE_DEBUG_INFO_H_