Pass FROM_HERE to ObserverListThreadSafe::Notify to improve profile.

components/storage_monitor/storage_monitor.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 "components/storage_monitor/storage_monitor.h"
 
 #include "base/stl_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "components/storage_monitor/removable_storage_observer.h"
 #include "components/storage_monitor/transient_device_ids.h"
@@ skipping 154 matching lines @@
       // This can happen if our unique id scheme fails. Ignore the incoming
       // non-unique attachment.
       return;
     }
     storage_map_.insert(std::make_pair(info.device_id(), info));
   }
 
   DVLOG(1) << "StorageAttached id " << info.device_id();
   if (StorageInfo::IsRemovableDevice(info.device_id())) {
     observer_list_->Notify(
-        &RemovableStorageObserver::OnRemovableStorageAttached, info);
+        FROM_HERE, &RemovableStorageObserver::OnRemovableStorageAttached, info);
   }
 }
 
 void StorageMonitor::ProcessDetach(const std::string& id) {
   StorageInfo info;
   {
     base::AutoLock lock(storage_lock_);
     StorageMap::iterator it = storage_map_.find(id);
     if (it == storage_map_.end())
       return;
     info = it->second;
     storage_map_.erase(it);
   }
 
   DVLOG(1) << "StorageDetached for id " << id;
   if (StorageInfo::IsRemovableDevice(info.device_id())) {
     observer_list_->Notify(
-        &RemovableStorageObserver::OnRemovableStorageDetached, info);
+        FROM_HERE, &RemovableStorageObserver::OnRemovableStorageDetached, info);
   }
 }
 
 }  // namespace storage_monitor