[memory-infra] Whitelist TabRestoreService MDP.

components/sessions/core/tab_restore_service_helper.cc

 // Copyright 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/sessions/core/tab_restore_service_helper.h"
 
 #include <inttypes.h>
 #include <stddef.h>
 
 #include <algorithm>
@@ skipping 330 matching lines @@
 
 bool TabRestoreServiceHelper::OnMemoryDump(
     const base::trace_event::MemoryDumpArgs& args,
     base::trace_event::ProcessMemoryDump* pmd) {
   using base::trace_event::MemoryAllocatorDump;
 
   const char* system_allocator_name =
       base::trace_event::MemoryDumpManager::GetInstance()
           ->system_allocator_pool_name();
 
+  if (entries_.empty()) {
+    // Nothing to report
+    return true;
+  }
+
   std::string entries_dump_name = base::StringPrintf(
       "tab_restore/service_helper_0x%" PRIXPTR "/entries",
       reinterpret_cast<uintptr_t>(this));
   pmd->CreateAllocatorDump(entries_dump_name)
       ->AddScalar(MemoryAllocatorDump::kNameObjectCount,
                   MemoryAllocatorDump::kUnitsObjects,
                   entries_.size());
 
   for (const auto& entry : entries_) {
     const char* type_string = "";
@@ skipping 190 matching lines @@
         tab.browser_id = new_id;
     }
   }
 }
 
 base::Time TabRestoreServiceHelper::TimeNow() const {
   return time_factory_ ? time_factory_->TimeNow() : base::Time::Now();
 }
 
 }  // namespace sessions