Oilpan: switch some leftover raw references over to traced Member<>s.

Source/modules/filesystem/DOMFileSystemBase.cpp

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 56 matching lines @@
     , m_type(type)
     , m_filesystemRootURL(rootURL)
     , m_clonable(false)
 {
 }
 
 DOMFileSystemBase::~DOMFileSystemBase()
 {
 }
 
+DEFINE_TRACE(DOMFileSystemBase)
+{
+    visitor->trace(m_context);
+}
+
 WebFileSystem* DOMFileSystemBase::fileSystem() const
 {
     Platform* platform = Platform::current();
     if (!platform)
         return nullptr;
     return platform->fileSystem();
 }
 
 SecurityOrigin* DOMFileSystemBase::securityOrigin() const
 {
@@ skipping 333 matching lines @@
         buffer.Resize(inputLength * 3);
 
     url::EncodeURIComponent(utf8.data(), inputLength, &buffer);
     String escaped(buffer.data(), buffer.length());
     // Unescape '/'; it's safe and much prettier.
     escaped.replace("%2F", "/");
     return escaped;
 }
 
 } // namespace blink