Remove Chromium plumbing for fixed-position-creates-stacking-context.

webkit/common/webpreferences.h

 // Copyright 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.
 //
 // A struct for managing webkit's settings.
 //
 // Adding new values to this class probably involves updating
 // blink::WebSettings, content/common/view_messages.h, browser/tab_contents/
 // render_view_host_delegate_helper.cc, and browser/profiles/profile.cc.
 
@@ skipping 113 matching lines @@
   bool should_clear_document_background;
   bool enable_scroll_animator;
   bool css_variables_enabled;
   bool lazy_layout_enabled;
   bool region_based_columns_enabled;
   bool touch_enabled;
   bool device_supports_touch;
   bool device_supports_mouse;
   bool touch_adjustment_enabled;
   int pointer_events_max_touch_points;
-  bool fixed_position_creates_stacking_context;
   bool sync_xhr_in_documents_enabled;
   bool deferred_image_decoding_enabled;
   bool should_respect_image_orientation;
   int number_of_cpu_cores;
   webkit_glue::EditingBehavior editing_behavior;
   bool supports_multiple_windows;
   bool viewport_enabled;
   bool viewport_meta_enabled;
   bool main_frame_resizes_are_orientation_changes;
   bool initialize_at_minimum_page_scale;
@@ skipping 38 matching lines @@
 #endif
 
   // We try to keep the default values the same as the default values in
   // chrome, except for the cases where it would require lots of extra work for
   // the embedder to use the same default value.
   WebPreferences();
   ~WebPreferences();
 };
 
 #endif  // WEBKIT_COMMON_WEBPREFERENCES_H__