[iOS][Common] Delete compatibility header

Bug: 1052505
Change-Id: I1af4911a8d927c3530d1d4c70451c556f6e67dfc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2089816
Commit-Queue: Javier Ernesto Flores Robles <javierrobles@chromium.org>
Commit-Queue: Sylvain Defresne <sdefresne@chromium.org>
Auto-Submit: Javier Ernesto Flores Robles <javierrobles@chromium.org>
Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#747298}

ios/chrome/common/colors/BUILD.gn

-# 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.
-
-source_set("colors") {
-  configs += [ "//build/config/compiler:enable_arc" ]
-  sources = [ "semantic_color_names.h" ]
-  deps = [ "//ios/chrome/common/ui/colors" ]
-}

ios/chrome/common/colors/semantic_color_names.h

-// Copyright 2020 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.
-
-// This file is temporal to not break internal.
-#import "ios/chrome/common/ui/colors/semantic_color_names.h"