[iOS] Factor out the KeyboardAccessoryView.

ios/chrome/browser/ui/toolbar/BUILD.gn

 # Copyright 2016 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.
 
 bundle_data("resources") {
   sources = [
     "resources/collapse.png",
     "resources/collapse@2x.png",
     "resources/collapse@3x.png",
     "resources/collapse_incognito.png",
@@ skipping 22 matching lines @@
     "resources/toolbar_dark_newtab_incognito_active@3x.png",
   ]
   outputs = [
     "{{bundle_resources_dir}}/{{source_file_part}}",
   ]
 }
 
 source_set("toolbar") {
   configs += [ "//build/config/compiler:enable_arc" ]
   sources = [
+    "keyboard_accessory_view.h",
+    "keyboard_accessory_view.mm",
     "new_tab_button.h",
     "new_tab_button.mm",
     "toolbar_button_tints.h",
     "toolbar_button_tints.mm",
     "toolbar_controller+protected.h",
     "toolbar_controller.h",
     "toolbar_controller.mm",
     "toolbar_controller_private.h",
     "toolbar_model_delegate_ios.h",
     "toolbar_model_delegate_ios.mm",
@@ skipping 150 matching lines @@
     "//ios/chrome/browser/ui/tools_menu",
     "//ios/chrome/test/app:test_support",
     "//ios/chrome/test/earl_grey:test_support",
     "//ios/testing/earl_grey:earl_grey_support",
     "//ios/third_party/earl_grey",
     "//ios/web:test_support",
     "//ui/base",
   ]
   libs = [ "XCTest.framework" ]
 }