Move FileEnumerator to its own file, do some refactoring.

third_party/zlib/google/zip_unittest.cc

Index: third_party/zlib/google/zip_unittest.cc
diff --git a/third_party/zlib/google/zip_unittest.cc b/third_party/zlib/google/zip_unittest.cc
index 3f7911e08a3d1d635f7495daa2992ca7a1b64c8e..e5d800bff6563975be4e0b344b8b5e945261e01a 100644
--- a/third_party/zlib/google/zip_unittest.cc
+++ b/third_party/zlib/google/zip_unittest.cc
@@ -6,6 +6,7 @@
 #include <vector>
 
 #include "base/file_util.h"
+#include "base/files/file_enumerator.h"
 #include "base/files/file_path.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/path_service.h"
@@ -73,9 +74,8 @@ class ZipTest : public PlatformTest {
     ASSERT_TRUE(file_util::PathExists(path)) << "no file " << path.value();
     ASSERT_TRUE(zip::Unzip(path, test_dir_));
 
-    file_util::FileEnumerator files(test_dir_, true,
-        file_util::FileEnumerator::FILES |
-        file_util::FileEnumerator::DIRECTORIES);
+    base::FileEnumerator files(test_dir_, true,
+        base::FileEnumerator::FILES | base::FileEnumerator::DIRECTORIES);
     base::FilePath next_path = files.Next();
     size_t count = 0;
     while (!next_path.value().empty()) {