Added --force-ui-direction flag for developers to force LTR or RTL.

base/BUILD.gn

 # Copyright (c) 2013 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.
 
 import("//build/config/compiler/compiler.gni")
 import("//build/config/nacl/config.gni")
 import("//build/config/ui.gni")
 import("//testing/test.gni")
 
 if (is_android) {
@@ skipping 987 matching lines @@
   if (!is_debug) {
     configs -= [ "//build/config/compiler:default_optimization" ]
     configs += [ "//build/config/compiler:optimize_max" ]
   }
 }
 
 component("i18n") {
   output_name = "base_i18n"
   sources = [
     "i18n/base_i18n_export.h",
+    "i18n/base_i18n_switches.cc",
+    "i18n/base_i18n_switches.h",
     "i18n/bidi_line_iterator.cc",
     "i18n/bidi_line_iterator.h",
     "i18n/break_iterator.cc",
     "i18n/break_iterator.h",
     "i18n/case_conversion.cc",
     "i18n/case_conversion.h",
     "i18n/char_iterator.cc",
     "i18n/char_iterator.h",
     "i18n/file_util_icu.cc",
     "i18n/file_util_icu.h",
@@ skipping 730 matching lines @@
 
   # GYP: //base.gyp:base_java_unittest_support
   android_library("base_java_unittest_support") {
     deps = [
       ":base_java",
     ]
     java_files =
         [ "test/android/java/src/org/chromium/base/ContentUriTestUtils.java" ]
   }
 }