[iOS] Remove temporary experimental flag file

The file was used for downstream compatibility.

Bug: none
Change-Id: Idd6baf6fd2542c3e67b49f1bec169d021922d79d
Reviewed-on: https://chromium-review.googlesource.com/c/1475407
Commit-Queue: Gauthier Ambard <gambard@chromium.org>
Reviewed-by: Eric Noyau <noyau@chromium.org>
Cr-Commit-Position: refs/heads/master@{#635464}

ios/chrome/browser/BUILD.gn

@@ -49,7 +49,6 @@ source_set("browser") {
     "chrome_url_util.mm",
     "crash_loop_detection_util.h",
     "crash_loop_detection_util.mm",
-    "experimental_flags.h",
     "file_metadata_util.h",
     "file_metadata_util.mm",
     "install_time_util.h",

ios/chrome/browser/experimental_flags.h

-// Copyright 2019 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef IOS_CHROME_BROWSER_EXPERIMENTAL_FLAGS_H_
-#define IOS_CHROME_BROWSER_EXPERIMENTAL_FLAGS_H_
-
-// This file is only temporary.
-#include "ios/chrome/browser/system_flags.h"
-
-#endif  // IOS_CHROME_BROWSER_EXPERIMENTAL_FLAGS_H_