[Sync] Implement EstimateMemoryUsage for SharedModelTypeProcessor and ModelTypeWorker

components/sync/model_impl/processor_entity_tracker.cc

Index: components/sync/model_impl/processor_entity_tracker.cc
diff --git a/components/sync/model_impl/processor_entity_tracker.cc b/components/sync/model_impl/processor_entity_tracker.cc
index ec12df89ae446939328f6ae56a924d91f2cb4b00..c468d464f482399defc4b40469a4251996dd29b0 100644
--- a/components/sync/model_impl/processor_entity_tracker.cc
+++ b/components/sync/model_impl/processor_entity_tracker.cc
@@ -6,8 +6,10 @@
 
 #include "base/base64.h"
 #include "base/sha1.h"
+#include "base/trace_event/memory_usage_estimator.h"
 #include "components/sync/base/time.h"
 #include "components/sync/engine/non_blocking_sync_common.h"
+#include "components/sync/protocol/proto_memory_estimations.h"
 
 namespace syncer {
 
@@ -239,6 +241,15 @@ void ProcessorEntityTracker::IncrementSequenceNumber() {
   metadata_.set_sequence_number(metadata_.sequence_number() + 1);
 }
 
+size_t ProcessorEntityTracker::EstimateMemoryUsage() const {
+  using base::trace_event::EstimateMemoryUsage;
+  size_t memory_usage = 0;
+  memory_usage += EstimateMemoryUsage(storage_key_);
+  memory_usage += EstimateMemoryUsage(metadata_);
+  memory_usage += EstimateMemoryUsage(commit_data_);
+  return memory_usage;
+}
+
 bool ProcessorEntityTracker::MatchesSpecificsHash(
     const sync_pb::EntitySpecifics& specifics) const {
   DCHECK(!metadata_.is_deleted());