[Sync] Implement MemoryDumpProvider.

components/sync/syncable/entry_kernel.cc

 // Copyright (c) 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.
 
 #include "components/sync/syncable/entry_kernel.h"
 
 #include <utility>
 
 #include "base/json/string_escape.h"
 #include "base/strings/string_number_conversions.h"
+#include "base/trace_event/memory_usage_estimator.h"
 #include "components/sync/base/cryptographer.h"
+#include "components/sync/protocol/proto_memory_estimations.h"
 #include "components/sync/protocol/proto_value_conversions.h"
 #include "components/sync/syncable/syncable_columns.h"
 #include "components/sync/syncable/syncable_enum_conversions.h"
 
 namespace syncer {
 namespace syncable {
 
-EntryKernel::EntryKernel() : dirty_(false) {
+EntryKernel::EntryKernel() : dirty_(false), memory_usage_(kMemoryUsageUnknown) {
   // Everything else should already be default-initialized.
   for (int i = 0; i < INT64_FIELDS_COUNT; ++i) {
     int64_fields[i] = 0;
   }
 }
 
 EntryKernel::EntryKernel(const EntryKernel& other) = default;
 
 EntryKernel::~EntryKernel() {}
 
@@ skipping 174 matching lines @@
                  &AttachmentMetadataToValue, ATTACHMENT_METADATA_FIELDS_BEGIN,
                  ATTACHMENT_METADATA_FIELDS_END - 1);
 
   // Bit temps.
   SetFieldValues(*this, kernel_info, &GetBitTempString, &BooleanToValue,
                  BIT_TEMPS_BEGIN, BIT_TEMPS_END - 1);
 
   return kernel_info;
 }
 
+size_t EntryKernel::EstimateMemoryUsage() const {
+  if (memory_usage_ == kMemoryUsageUnknown) {
+    using base::trace_event::EstimateMemoryUsage;
+    memory_usage_ = EstimateMemoryUsage(string_fields) +
+                    EstimateMemoryUsage(specifics_fields) +
+                    EstimateMemoryUsage(id_fields) +
+                    EstimateMemoryUsage(unique_position_fields) +
+                    EstimateMemoryUsage(attachment_metadata_fields);
+  }
+  return memory_usage_;
+}
+
 std::unique_ptr<base::ListValue> EntryKernelMutationMapToValue(
     const EntryKernelMutationMap& mutations) {
   std::unique_ptr<base::ListValue> list(new base::ListValue());
   for (EntryKernelMutationMap::const_iterator it = mutations.begin();
        it != mutations.end(); ++it) {
     list->Append(EntryKernelMutationToValue(it->second));
   }
   return list;
 }
 
@@ skipping 49 matching lines @@
   os << "TempFlags: ";
   for (; i < BIT_TEMPS_END; ++i) {
     if (kernel->ref(static_cast<BitTemp>(i)))
       os << "#" << i - BIT_TEMPS_BEGIN << ", ";
   }
   return os;
 }
 
 }  // namespace syncable
 }  // namespace syncer