Move FileEnumerator to its own file, do some refactoring.

net/disk_cache/cache_util_posix.cc

Index: net/disk_cache/cache_util_posix.cc
diff --git a/net/disk_cache/cache_util_posix.cc b/net/disk_cache/cache_util_posix.cc
index 3cc9f3b488bba8ba27d45ea2eb841cad162f4410..ffd810786409b06c44da9223c8bf850e83032e89 100644
--- a/net/disk_cache/cache_util_posix.cc
+++ b/net/disk_cache/cache_util_posix.cc
@@ -5,6 +5,7 @@
 #include "net/disk_cache/cache_util.h"
 
 #include "base/file_util.h"
+#include "base/files/file_enumerator.h"
 #include "base/logging.h"
 #include "base/string_util.h"
 
@@ -22,9 +23,8 @@ bool MoveCache(const base::FilePath& from_path, const base::FilePath& to_path) {
     LOG(ERROR) << "Unable to create destination cache directory.";
     return false;
   }
-  file_util::FileEnumerator iter(from_path, false /* not recursive */,
-      file_util::FileEnumerator::DIRECTORIES |
-      file_util::FileEnumerator::FILES);
+  base::FileEnumerator iter(from_path, false /* not recursive */,
+      base::FileEnumerator::DIRECTORIES | base::FileEnumerator::FILES);
   for (base::FilePath name = iter.Next(); !name.value().empty();
        name = iter.Next()) {
     base::FilePath destination = to_path.Append(name.BaseName());
@@ -40,9 +40,9 @@ bool MoveCache(const base::FilePath& from_path, const base::FilePath& to_path) {
 }
 
 void DeleteCache(const base::FilePath& path, bool remove_folder) {
-  file_util::FileEnumerator iter(path,
-                                 /* recursive */ false,
-                                 file_util::FileEnumerator::FILES);
+  base::FileEnumerator iter(path,
+                            /* recursive */ false,
+                            base::FileEnumerator::FILES);
   for (base::FilePath file = iter.Next(); !file.value().empty();
        file = iter.Next()) {
     if (!file_util::Delete(file, /* recursive */ false)) {