[Sync] Implement MemoryDumpProvider.

components/sync/syncable/directory.cc

Index: components/sync/syncable/directory.cc
diff --git a/components/sync/syncable/directory.cc b/components/sync/syncable/directory.cc
index 0671977d126b6cad86d829eecbf54b5f4b1e9505..c49c74bded92a6ba4853620e2f9cf365b48490a1 100644
--- a/components/sync/syncable/directory.cc
+++ b/components/sync/syncable/directory.cc
@@ -4,6 +4,8 @@
 
 #include "components/sync/syncable/directory.h"
 
+#include <inttypes.h>
+
 #include <algorithm>
 #include <iterator>
 #include <utility>
@@ -13,10 +15,15 @@
 #include "base/memory/ptr_util.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/strings/string_number_conversions.h"
+#include "base/strings/stringprintf.h"
+#include "base/trace_event/estimate_memory_usage.h"

[pavely, 2016/10/28 22:55:32]

Is estimate_memory_usage.h a new file? I can't find it.

+#include "base/trace_event/memory_dump_manager.h"
+#include "base/trace_event/process_memory_dump.h"
 #include "base/trace_event/trace_event.h"
 #include "components/sync/base/attachment_id_proto.h"
 #include "components/sync/base/unique_position.h"
 #include "components/sync/base/unrecoverable_error_handler.h"
+#include "components/sync/protocol/proto_memory_estimations.h"
 #include "components/sync/syncable/in_memory_directory_backing_store.h"
 #include "components/sync/syncable/model_neutral_mutable_entry.h"
 #include "components/sync/syncable/on_disk_directory_backing_store.h"
@@ -66,6 +73,14 @@ bool Directory::PersistedKernelInfo::HasEmptyDownloadProgress(
   return progress_marker.token().empty();
 }
 
+size_t Directory::PersistedKernelInfo::EstimateMemoryUsage() const {
+  using base::trace_event::EstimateMemoryUsage;
+  return EstimateMemoryUsage(store_birthday) +
+         EstimateMemoryUsage(bag_of_chips) +
+         EstimateMemoryUsage(datatype_context);
+
+}
+
 Directory::SaveChangesSnapshot::SaveChangesSnapshot()
     : kernel_info_status(KERNEL_SHARE_INFO_INVALID) {}
 
@@ -885,6 +900,55 @@ size_t Directory::GetEntriesCount() const {
   return kernel_->metahandles_map.size();
 }
 
+void Directory::OnMemoryDump(base::trace_event::ProcessMemoryDump* pmd) {
+  std::string dump_name_base = base::StringPrintf(
+      "sync/0x%" PRIXPTR, reinterpret_cast<uintptr_t>(this));
+
+  size_t kernel_memory_usage;
+  {
+    using base::trace_event::EstimateMemoryUsage;
+
+    ScopedKernelLock lock(this); // TODO(dskiba): is this the correct lock?
+    kernel_memory_usage =
+        EstimateMemoryUsage(kernel_->name) +
+        EstimateMemoryUsage(kernel_->metahandles_map) +

[pavely, 2016/10/28 22:55:32]

I can't see implementation of EstimateMemoryUsage, but I assume it will iterate
over collection and call EstimateMemoryUsage on values. If that's the case then
you'll need to take both locks:
  syncable::ReadTransaction trans(FROM_HERE, this);
  ScopedKernelLock lock(this);

+        EstimateMemoryUsage(kernel_->ids_map) +
+        EstimateMemoryUsage(kernel_->server_tags_map) +
+        EstimateMemoryUsage(kernel_->client_tags_map) +
+        // TODO(dskiba): EstimateMemoryUsage(kernel_->parent_child_index) +
+        EstimateMemoryUsage(kernel_->index_by_attachment_id) +
+        EstimateMemoryUsage(kernel_->unapplied_update_metahandles) +
+        EstimateMemoryUsage(kernel_->unsynced_metahandles) +
+        EstimateMemoryUsage(kernel_->dirty_metahandles) +
+        EstimateMemoryUsage(kernel_->metahandles_to_purge) +
+        EstimateMemoryUsage(kernel_->persisted_info) +
+        EstimateMemoryUsage(kernel_->cache_guid);
+  }
+
+  {
+    std::string dump_name = base::StringPrintf(
+        "%s/kernel", dump_name_base.c_str());
+
+    auto* dump = pmd->CreateAllocatorDump(dump_name);
+    dump->AddScalar(base::trace_event::MemoryAllocatorDump::kNameSize,
+                    base::trace_event::MemoryAllocatorDump::kUnitsBytes,
+                    kernel_memory_usage);
+    const char* system_allocator_name =
+        base::trace_event::MemoryDumpManager::GetInstance()
+            ->system_allocator_pool_name();
+    if (system_allocator_name) {
+      pmd->AddSuballocation(dump->guid(), system_allocator_name);
+    }
+  }
+
+  if (store_) {
+    std::string dump_name = base::StringPrintf(
+        "%s/store", dump_name_base.c_str());
+    auto* dump = pmd->CreateAllocatorDump(dump_name);
+    store_->ReportMemoryUsage(dump);
+  }
+}
+
 void Directory::SetDownloadProgress(
     ModelType model_type,
     const sync_pb::DataTypeProgressMarker& new_progress) {