Add command line switch to enable region based columns.

webkit/renderer/webpreferences_renderer.cc

Index: webkit/renderer/webpreferences_renderer.cc
diff --git a/webkit/renderer/webpreferences_renderer.cc b/webkit/renderer/webpreferences_renderer.cc
index 9e0e5173027cb5993ab0696b5b36ddf40ba92eab..b7961bd86dd01b03ed9f81930ff5ad2f8b93e2c1 100644
--- a/webkit/renderer/webpreferences_renderer.cc
+++ b/webkit/renderer/webpreferences_renderer.cc
@@ -288,6 +288,7 @@ void ApplyWebPreferences(const WebPreferences& prefs, WebView* web_view) {
   settings->setCSSStickyPositionEnabled(prefs.css_sticky_position_enabled);
   settings->setExperimentalCSSCustomFilterEnabled(prefs.css_shaders_enabled);
   settings->setExperimentalCSSGridLayoutEnabled(prefs.css_grid_layout_enabled);
+  settings->setRegionBasedColumnsEnabled(prefs.region_based_columns_enabled);
 
   WebRuntimeFeatures::enableLazyLayout(prefs.lazy_layout_enabled);
   WebRuntimeFeatures::enableTouch(prefs.touch_enabled);