Add MDP for TabRestorer.

components/sessions/core/tab_restore_service_helper.cc

Index: components/sessions/core/tab_restore_service_helper.cc
diff --git a/components/sessions/core/tab_restore_service_helper.cc b/components/sessions/core/tab_restore_service_helper.cc
index 841f07594df1dd636831b88046e525ae4c2735eb..72ed43a9317072f6962d911270537352916cb906 100644
--- a/components/sessions/core/tab_restore_service_helper.cc
+++ b/components/sessions/core/tab_restore_service_helper.cc
@@ -4,6 +4,7 @@
 
 #include "components/sessions/core/tab_restore_service_helper.h"
 
+#include <inttypes.h>
 #include <stddef.h>
 
 #include <algorithm>
@@ -13,6 +14,10 @@
 #include "base/memory/ptr_util.h"
 #include "base/metrics/histogram.h"
 #include "base/stl_util.h"
+#include "base/strings/stringprintf.h"
+#include "base/trace_event/estimate_memory_usage.h"
+#include "base/trace_event/memory_dump_manager.h"
+#include "base/trace_event/process_memory_dump.h"
 #include "components/sessions/core/live_tab.h"
 #include "components/sessions/core/live_tab_context.h"
 #include "components/sessions/core/serialized_navigation_entry.h"
@@ -327,6 +332,28 @@ TabRestoreServiceHelper::GetEntryIteratorById(SessionID::id_type id) {
   return entries_.end();
 }
 
+bool TabRestoreServiceHelper::OnMemoryDump(
+    const base::trace_event::MemoryDumpArgs& args,
+    base::trace_event::ProcessMemoryDump* pmd) {
+  using base::trace_event::EstimateMemoryUsage;
+  size_t memory_usage = EstimateMemoryUsage(entries_);
+
+  std::string dump_name = base::StringPrintf(
+      "tab_restore/0x%" PRIXPTR, reinterpret_cast<uintptr_t>(this));
+  auto* dump = pmd->CreateAllocatorDump(dump_name);
+  dump->AddScalar(base::trace_event::MemoryAllocatorDump::kNameSize,
+                  base::trace_event::MemoryAllocatorDump::kUnitsBytes,
+                  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);
+  }
+
+  return true;
+}
+
 // static
 bool TabRestoreServiceHelper::ValidateEntry(const Entry& entry) {
   switch (entry.type) {