Move file_util to base/files/ directory.

base/BUILD.gn

Index: base/BUILD.gn
diff --git a/base/BUILD.gn b/base/BUILD.gn
index 79549724f69dbd5c1acc21fdb9ef8fad91c30737..9952af0b8dbcfc1ebb60a6b353366ff03de893be 100644
--- a/base/BUILD.gn
+++ b/base/BUILD.gn
@@ -173,13 +173,6 @@ component("base") {
     "event_recorder.h",
     "event_recorder_win.cc",
     "file_descriptor_posix.h",
-    "file_util.cc",
-    "file_util.h",
-    "file_util_android.cc",
-    "file_util_linux.cc",
-    "file_util_mac.mm",
-    "file_util_posix.cc",
-    "file_util_win.cc",
     "file_version_info.h",
     "file_version_info_mac.h",
     "file_version_info_mac.mm",
@@ -209,8 +202,15 @@ component("base") {
     "files/file_path_watcher_win.cc",
     "files/file_proxy.cc",
     "files/file_proxy.h",
+    "files/file_util.cc",
+    "files/file_util.h",
+    "files/file_util_android.cc",
+    "files/file_util_linux.cc",
+    "files/file_util_mac.mm",
+    "files/file_util_posix.cc",
     "files/file_util_proxy.cc",
     "files/file_util_proxy.h",
+    "files/file_util_win.cc",
     "files/important_file_writer.cc",
     "files/important_file_writer.h",
     "files/memory_mapped_file.cc",
@@ -799,7 +799,7 @@ component("base") {
     sources -= [
       "debug/stack_trace_posix.cc",
       "files/file_enumerator_posix.cc",
-      "file_util_posix.cc",
+      "files/file_util_posix.cc",
       "message_loop/message_pump_libevent.cc",
       "process/kill_posix.cc",
       "process/launch_posix.cc",
@@ -1084,13 +1084,13 @@ test("base_unittests") {
     "debug/trace_event_win_unittest.cc",
     "deferred_sequenced_task_runner_unittest.cc",
     "environment_unittest.cc",
-    "file_util_unittest.cc",
     "file_version_info_unittest.cc",
     "files/dir_reader_posix_unittest.cc",
     "files/file_path_unittest.cc",
     "files/file_proxy_unittest.cc",
     "files/file_unittest.cc",
     "files/file_util_proxy_unittest.cc",
+    "files/file_util_unittest.cc",
     "files/important_file_writer_unittest.cc",
     "files/scoped_temp_dir_unittest.cc",
     "gmock_unittest.cc",