Move undo files into //components/undo

components/undo.gypi

+# Copyright 2015 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.
+
+{
+  'targets': [
+    {
+      # GN version: //components/undo
+      'target_name': 'undo_component',
+      'type': 'static_library',
+      'include_dirs': [
+        '..',
+      ],
+      'dependencies': [
+        '../base/base.gyp:base',
+        '../ui/base/ui_base.gyp:ui_base',
+        'bookmarks_browser',
+        'components_strings.gyp:components_strings',
+        'keyed_service_core',
+      ],
+      'sources': [
+        'undo/bookmark_renumber_observer.h',
+        'undo/bookmark_undo_service.cc',
+        'undo/bookmark_undo_service.h',
+        'undo/bookmark_undo_utils.cc',
+        'undo/bookmark_undo_utils.h',
+        'undo/undo_manager.cc',
+        'undo/undo_manager.h',
+        'undo/undo_manager_observer.h',
+        'undo/undo_operation.h',
+      ],
+    },
+  ],
+}