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

components/sync/driver/data_type_controller.h

 // Copyright 2014 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_DRIVER_DATA_TYPE_CONTROLLER_H__
 #define COMPONENTS_SYNC_DRIVER_DATA_TYPE_CONTROLLER_H__
 
 #include <map>
 #include <memory>
 #include <string>
@@ skipping 144 matching lines @@
   // Returns a ListValue representing all nodes for this data type through
   // |callback| on this thread.
   // Used for populating nodes in Sync Node Browser of chrome://sync-internals.
   virtual void GetAllNodes(const AllNodesCallback& callback) = 0;
 
   // Collects StatusCounters for this datatype and passes them to |callback|,
   // which should be wrapped with syncer::BindToCurrentThread already.
   // Used to display entity counts in chrome://sync-internals.
   virtual void GetStatusCounters(const StatusCountersCallback& callback) = 0;
 
+  // Estimates memory usage of type and records it into histogram.
+  virtual void RecordMemoryUsageHistogram() = 0;
+
  protected:
   explicit DataTypeController(ModelType type);
 
   // Allows subclasses to DCHECK that they're on the correct thread.
   bool CalledOnValidThread() const;
 
  private:
   // The type this object is responsible for controlling.
   const ModelType type_;
 
   // Used to check that functions are called on the correct thread.
   base::ThreadChecker thread_checker_;
 };
 
 }  // namespace syncer
 
 #endif  // COMPONENTS_SYNC_DRIVER_DATA_TYPE_CONTROLLER_H__