Replace base::NullableString16(bool) usage with default constructor.

content/browser/dom_storage/dom_storage_message_filter.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 "content/browser/dom_storage/dom_storage_message_filter.h"
 
 #include "base/auto_reset.h"
 #include "base/bind.h"
 #include "base/strings/nullable_string16.h"
 #include "base/strings/utf_string_conversions.h"
@@ skipping 155 matching lines @@
                       old_value);
 }
 
 void DOMStorageMessageFilter::OnDomStorageItemRemoved(
     const dom_storage::DomStorageArea* area,
     const string16& key,
     const string16& old_value,
     const GURL& page_url) {
   SendDomStorageEvent(area, page_url,
                       base::NullableString16(key, false),
-                      base::NullableString16(true),
+                      base::NullableString16(),
                       base::NullableString16(old_value, false));
 }
 
 void DOMStorageMessageFilter::OnDomStorageAreaCleared(
     const dom_storage::DomStorageArea* area,
     const GURL& page_url) {
   SendDomStorageEvent(area, page_url,
-                      base::NullableString16(true),
-                      base::NullableString16(true),
-                      base::NullableString16(true));
+                      base::NullableString16(),
+                      base::NullableString16(),
+                      base::NullableString16());
 }
 
 void DOMStorageMessageFilter::SendDomStorageEvent(
     const dom_storage::DomStorageArea* area,
     const GURL& page_url,
     const base::NullableString16& key,
     const base::NullableString16& new_value,
     const base::NullableString16& old_value) {
   DCHECK(!BrowserThread::CurrentlyOn(BrowserThread::IO));
   // Only send mutation events to processes which have the area open.
   bool originated_in_process = connection_dispatching_message_for_ != 0;
   if (originated_in_process ||
       host_->HasAreaOpen(area->namespace_id(), area->origin())) {
     DOMStorageMsg_Event_Params params;
     params.origin = area->origin();
     params.page_url = page_url;
     params.connection_id = connection_dispatching_message_for_;
     params.key = key;
     params.new_value = new_value;
     params.old_value = old_value;
     params.namespace_id = area->namespace_id();
     Send(new DOMStorageMsg_Event(params));
   }
 }
 
 }  // namespace content