Remove std::string histogram name from HistogramBase object.

extensions/browser/value_store/leveldb_value_store.cc

 // Copyright 2014 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 "extensions/browser/value_store/leveldb_value_store.h"
 
 #include <inttypes.h>
 #include <stdint.h>
 
 #include <utility>
@@ skipping 236 matching lines @@
     return true;
 
   std::string value;
   uint64_t size;
   bool res = db()->GetProperty("leveldb.approximate-memory-usage", &value);
   DCHECK(res);
   res = base::StringToUint64(value, &size);
   DCHECK(res);
 
   auto* dump = pmd->CreateAllocatorDump(base::StringPrintf(
-      "leveldb/value_store/%s/0x%" PRIXPTR, open_histogram_name().c_str(),
+      "leveldb/value_store/%s/0x%" PRIXPTR, open_histogram_name(),
       reinterpret_cast<uintptr_t>(this)));
   dump->AddScalar(base::trace_event::MemoryAllocatorDump::kNameSize,
                   base::trace_event::MemoryAllocatorDump::kUnitsBytes, size);
 
   // All leveldb databases are already dumped by leveldb_env::DBTracker. Add
   // an edge to avoid double counting.
   pmd->AddSuballocation(dump->guid(),
                         leveldb_env::DBTracker::GetMemoryDumpName(db()));
 
   return true;
@@ skipping 26 matching lines @@
       return Status(OTHER_ERROR, kCannotSerialize);
     batch->Put(key, value_as_json);
   }
 
   return Status();
 }
 
 ValueStore::Status LeveldbValueStore::WriteToDb(leveldb::WriteBatch* batch) {
   return ToValueStoreError(db()->Write(write_options(), batch));
 }