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

content/browser/renderer_host/render_view_host_impl.cc

Index: content/browser/renderer_host/render_view_host_impl.cc
diff --git a/content/browser/renderer_host/render_view_host_impl.cc b/content/browser/renderer_host/render_view_host_impl.cc
index a6f7a4567da0a113b7945b2b8058d651d49377af..54437614344564349b91c74f4f79988d5011b036 100644
--- a/content/browser/renderer_host/render_view_host_impl.cc
+++ b/content/browser/renderer_host/render_view_host_impl.cc
@@ -434,8 +434,6 @@ WebPreferences RenderViewHostImpl::ComputeWebkitPrefs() {
   prefs.text_blobs_enabled = command_line.HasSwitch(switches::kForceTextBlobs)
       || (content::IsImplSidePaintingEnabled() &&
           !command_line.HasSwitch(switches::kDisableTextBlobs));
-  prefs.region_based_columns_enabled =
-      command_line.HasSwitch(switches::kEnableRegionBasedColumns);
 
   if (IsPinchVirtualViewportEnabled()) {
     prefs.pinch_virtual_viewport_enabled = true;