Replace ASSERT with DCHECK in core/

third_party/WebKit/Source/core/clipboard/DraggedIsolatedFileSystem.cpp

 // Copyright 2015 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 "core/clipboard/DraggedIsolatedFileSystem.h"
 
 namespace blink {
 
 DraggedIsolatedFileSystem::FileSystemIdPreparationCallback
     DraggedIsolatedFileSystem::prepare_callback_ = nullptr;
 
 void DraggedIsolatedFileSystem::Init(
     DraggedIsolatedFileSystem::FileSystemIdPreparationCallback callback) {
-  ASSERT(!prepare_callback_);
+  DCHECK(!prepare_callback_);
   prepare_callback_ = callback;
 }
 
 void DraggedIsolatedFileSystem::PrepareForDataObject(DataObject* data_object) {
-  ASSERT(prepare_callback_);
+  DCHECK(prepare_callback_);
   (*prepare_callback_)(data_object);
 }
 
 }  // namespace blink