Mandate unique_ptr for base::IDMap in IDMapOwnPointer mode.

chrome/browser/metrics/subprocess_metrics_provider.cc

 // Copyright 2016 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 "chrome/browser/metrics/subprocess_metrics_provider.h"
 
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
 #include "base/metrics/histogram_base.h"
 #include "base/metrics/histogram_macros.h"
@@ skipping 41 matching lines @@
   DCHECK(thread_checker_.CalledOnValidThread());
   DCHECK(!allocators_by_id_.Lookup(id));
 
   // Stop now if this was called without an allocator, typically because
   // GetSubprocessHistogramAllocatorOnIOThread exited early and returned
   // null.
   if (!allocator)
     return;
 
   // Map is "MapOwnPointer" so transfer ownership to it.
-  allocators_by_id_.AddWithID(allocator.release(), id);
+  allocators_by_id_.AddWithID(std::move(allocator), id);
 }
 
 void SubprocessMetricsProvider::DeregisterSubprocessAllocator(int id) {
   DCHECK(thread_checker_.CalledOnValidThread());
 
   if (!allocators_by_id_.Lookup(id))
     return;
 
   // Extract the matching allocator from the list of active ones. It will
   // be automatically released when this method exits.
@@ skipping 140 matching lines @@
     return nullptr;
 
   std::unique_ptr<base::SharedPersistentMemoryAllocator> allocator =
       host->TakeMetricsAllocator();
   if (!allocator)
     return nullptr;
 
   return base::MakeUnique<base::PersistentHistogramAllocator>(
       std::move(allocator));
 }