[Refactor] to rename and re-layer the file_util stack layers.

webkit/fileapi/quota_file_util.cc

Index: webkit/fileapi/quota_file_util.cc
diff --git a/webkit/fileapi/quota_file_util.cc b/webkit/fileapi/quota_file_util.cc
index 56fbcb7a033a36033272be0f926f39e295b4af04..0de1277f7a353874b89cae4e6b017bf8cae2df5b 100644
--- a/webkit/fileapi/quota_file_util.cc
+++ b/webkit/fileapi/quota_file_util.cc
@@ -10,6 +10,7 @@
 #include "webkit/fileapi/file_system_operation_context.h"
 #include "webkit/fileapi/file_system_path_manager.h"
 #include "webkit/fileapi/file_system_quota_util.h"
+#include "webkit/fileapi/native_file_util.h"
 #include "webkit/quota/quota_manager.h"
 
 using quota::QuotaManagerProxy;
@@ -70,8 +71,8 @@ class ScopedOriginUpdateHelper {
 
 }  // namespace (anonymous)
 
-QuotaFileUtil::QuotaFileUtil(FileSystemFileUtil* underlying_file_util)
-    : underlying_file_util_(underlying_file_util) {
+QuotaFileUtil::QuotaFileUtil(FileUtil* underlying_file_util)
+    : OverlayFileUtil(underlying_file_util) {
 }
 
 QuotaFileUtil::~QuotaFileUtil() {
@@ -79,7 +80,7 @@ QuotaFileUtil::~QuotaFileUtil() {
 
 // static
 QuotaFileUtil* QuotaFileUtil::CreateDefault() {
-  return new QuotaFileUtil(new FileSystemFileUtil());
+  return new QuotaFileUtil(new NativeFileUtil());
 }
 
 int64 QuotaFileUtil::ComputeFilePathCost(const FilePath& file_path) const {
@@ -169,7 +170,7 @@ PlatformFileError QuotaFileUtil::CreateDirectory(
       FilePath last_path;
       for (FilePath path = fs_context->src_virtual_path();
            path.value() != last_path.value() &&
-               !fs_context->src_file_system_file_util()->PathExists(
+               !fs_context->src_file_util()->PathExists(
                    fs_context, fs_context->src_virtual_path());
            path = path.DirName()) {
         growth += ComputeFilePathCost(fs_context->src_virtual_path());