Pass FROM_HERE to ObserverListThreadSafe::Notify to improve profile.

base/metrics/field_trial.cc

 // Copyright (c) 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 "base/metrics/field_trial.h"
 
 #include <algorithm>
 
 #include "base/build_time.h"
 #include "base/logging.h"
@@ skipping 529 matching lines @@
     AutoLock auto_lock(global_->lock_);
     if (field_trial->group_reported_)
       return;
     field_trial->group_reported_ = true;
   }
 
   if (!field_trial->enable_field_trial_)
     return;
 
   global_->observer_list_->Notify(
-      &FieldTrialList::Observer::OnFieldTrialGroupFinalized,
-      field_trial->trial_name(),
-      field_trial->group_name_internal());
+      FROM_HERE, &FieldTrialList::Observer::OnFieldTrialGroupFinalized,
+      field_trial->trial_name(), field_trial->group_name_internal());
 }
 
 // static
 size_t FieldTrialList::GetFieldTrialCount() {
   if (!global_)
     return 0;
   AutoLock auto_lock(global_->lock_);
   return global_->registered_.size();
 }
 
@@ skipping 22 matching lines @@
     return;
   }
   AutoLock auto_lock(global_->lock_);
   DCHECK(!global_->PreLockedFind(trial->trial_name()));
   trial->AddRef();
   trial->SetTrialRegistered();
   global_->registered_[trial->trial_name()] = trial;
 }
 
 }  // namespace base