Move WriteFile and WriteFileDescriptor from file_util to base namespace.

base/files/file_path_watcher_browsertest.cc

Index: base/files/file_path_watcher_browsertest.cc
diff --git a/base/files/file_path_watcher_browsertest.cc b/base/files/file_path_watcher_browsertest.cc
index aed409c78714ed9d2f3ce8d1c3ee6f678eef2286..1260700a95ceb48a0909cea8071e54d0354b25f1 100644
--- a/base/files/file_path_watcher_browsertest.cc
+++ b/base/files/file_path_watcher_browsertest.cc
@@ -172,8 +172,7 @@ class FilePathWatcherTest : public testing::Test {
 
   // Write |content| to |file|. Returns true on success.
   bool WriteFile(const FilePath& file, const std::string& content) {
-    int write_size = file_util::WriteFile(file, content.c_str(),
-                                          content.length());
+    int write_size = WriteFile(file, content.c_str(), content.length());
     return write_size == static_cast<int>(content.length());
   }