Replicate to all renderers the accepted languages set by a layout test.

components/test_runner/layout_test_runtime_flags.cc

 // 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.
 
 #include "components/test_runner/layout_test_runtime_flags.h"
 
 namespace test_runner {
 
 LayoutTestRuntimeFlags::LayoutTestRuntimeFlags() {
   Reset();
 }
 
 void LayoutTestRuntimeFlags::Reset() {
   set_generate_pixel_results(true);
 
   set_dump_as_text(false);
   set_dump_child_frames_as_text(false);
 
   set_dump_as_markup(false);
   set_dump_child_frames_as_markup(false);
 
   set_dump_child_frame_scroll_positions(false);
 
   set_is_printing(false);
 
   set_wait_until_done(false);
 
+  set_accept_languages("");
+
   // No need to report the initial state - only the future delta is important.
   tracked_dictionary().ResetChangeTracking();
 }
 
 }  // namespace test_runner