[ios] Creates ToolsMenuConstants file

ios/chrome/browser/ui/tools_menu/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.
 
 source_set("tools_menu") {
   sources = [
     "reading_list_menu_view_item.h",
     "reading_list_menu_view_item.mm",
+    "tools_menu_constants.h",

[edchin, 2017/02/27 23:02:41]

Would we later move this to //ios/shared?

[sczs, 2017/03/02 22:56:11]

Since I don't want to keep updating the tests I will move it now :) Thanks for
pointing this out. 

+    "tools_menu_constants.mm",
     "tools_menu_context.h",
     "tools_menu_context.mm",
     "tools_menu_model.h",
     "tools_menu_model.mm",
     "tools_menu_view_controller.h",
     "tools_menu_view_controller.mm",
     "tools_menu_view_item.h",
     "tools_menu_view_item.mm",
     "tools_menu_view_tools_cell.h",
     "tools_menu_view_tools_cell.mm",
@@ skipping 53 matching lines @@
     "//ios/chrome/browser/ui",
     "//ios/chrome/browser/ui:ui_internal",
     "//ios/chrome/browser/ui/toolbar",
     "//ios/chrome/test/earl_grey:test_support",
     "//ios/third_party/earl_grey",
     "//ios/web:test_support",
     "//ui/base",
   ]
   libs = [ "XCTest.framework" ]
 }