Move Posix file utils to the base namespace.

content/common/set_process_title.cc

Index: content/common/set_process_title.cc
diff --git a/content/common/set_process_title.cc b/content/common/set_process_title.cc
index 6fde51bd6cbb92b5f70eda2526d7d7a5b44d5c32..5113ee03d97f17b666bd47c5102d7fc58411b014 100644
--- a/content/common/set_process_title.cc
+++ b/content/common/set_process_title.cc
@@ -50,7 +50,7 @@ void SetProcessTitleFromCommandLine(const char** main_argv) {
   // display purposes and has no TOCTTOU security implications.
   base::FilePath target;
   base::FilePath self_exe(base::kProcSelfExe);
-  if (file_util::ReadSymbolicLink(self_exe, &target)) {
+  if (base::ReadSymbolicLink(self_exe, &target)) {
     have_argv0 = true;
     title = target.value();
     // If the binary has since been deleted, Linux appends " (deleted)" to the