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

tools/android/md5sum/md5sum.cc

Index: tools/android/md5sum/md5sum.cc
diff --git a/tools/android/md5sum/md5sum.cc b/tools/android/md5sum/md5sum.cc
index 8543fb69950adb7b60053a24395649a2a4ec21e1..bc4ca071b8cd08bc8a6db4a411777ad422ce86ed 100644
--- a/tools/android/md5sum/md5sum.cc
+++ b/tools/android/md5sum/md5sum.cc
@@ -53,7 +53,7 @@ std::set<std::string> MakeFileSet(const char** files) {
   std::set<std::string> file_set;
   for (const char** file = files; *file; ++file) {
     base::FilePath file_path(*file);
-    if (file_util::DirectoryExists(file_path)) {
+    if (base::DirectoryExists(file_path)) {
       base::FileEnumerator file_enumerator(
           file_path, true /* recurse */, base::FileEnumerator::FILES);
       for (base::FilePath child, empty;