Remove --enable-region-based-columns command line flag.

content/renderer/render_view_impl.cc

Index: content/renderer/render_view_impl.cc
diff --git a/content/renderer/render_view_impl.cc b/content/renderer/render_view_impl.cc
index 48df2c47c64f2d302060d6147a322e480872294d..029d42154ec23f5037a4d6d10a21947de6772ffd 100644
--- a/content/renderer/render_view_impl.cc
+++ b/content/renderer/render_view_impl.cc
@@ -1013,8 +1013,6 @@ void RenderView::ApplyWebPreferences(const WebPreferences& prefs,
       prefs.should_clear_document_background);
   settings->setEnableScrollAnimator(prefs.enable_scroll_animator);
 
-  settings->setRegionBasedColumnsEnabled(prefs.region_based_columns_enabled);
-
   WebRuntimeFeatures::enableTouch(prefs.touch_enabled);
   settings->setMaxTouchPoints(prefs.pointer_events_max_touch_points);
   settings->setAvailablePointerTypes(prefs.available_pointer_types);