Move PathIsWritable, DirectoryExists, ContentsEqual, and TextContentsEqual to the base namespace.

chrome_frame/test/test_with_web_server.cc

Index: chrome_frame/test/test_with_web_server.cc
diff --git a/chrome_frame/test/test_with_web_server.cc b/chrome_frame/test/test_with_web_server.cc
index 9c93a37709b6f2cac5fc3ec5a4cce89238777634..06869adeff0c5418e3d8cef849010152cc9a0deb 100644
--- a/chrome_frame/test/test_with_web_server.cc
+++ b/chrome_frame/test/test_with_web_server.cc
@@ -400,7 +400,7 @@ void MockWebServer::SendResponseHelper(
   std::string headers, body;
   std::string content_type;
   if (base::PathExists(file_path) &&
-      !file_util::DirectoryExists(file_path)) {
+      !base::DirectoryExists(file_path)) {
     base::FilePath mock_http_headers(file_path.value() + L".mock-http-headers");
     if (base::PathExists(mock_http_headers)) {
       headers = GetMockHttpHeaders(mock_http_headers);