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

content/public/common/content_switches.cc

 // Copyright (c) 2012 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 "content/public/common/content_switches.h"
 
 namespace switches {
 
 // The number of MSAA samples for canvas2D. Requires MSAA support by GPU to
 // have an effect. 0 disables MSAA.
@@ skipping 384 matching lines @@
 const char kV8CacheOptions[] = "v8-cache-options";
 
 // Signals that the V8 natives file has been transfered to the child process
 // by a file descriptor.
 const char kV8NativesPassedByFD[] = "v8-natives-passed-by-fd";
 
 // Signals that the V8 startup snapshot file has been transfered to the child
 // process by a file descriptor.
 const char kV8SnapshotPassedByFD[] = "v8-snapshot-passed-by-fd";
 
-// Enables the CSS multicol implementation that uses the regions implementation.
-const char kEnableRegionBasedColumns[] =
-    "enable-region-based-columns";
-
 // Cause the OS X sandbox write to syslog every time an access to a resource
 // is denied by the sandbox.
 const char kEnableSandboxLogging[]          = "enable-sandbox-logging";
 
 // Enables seccomp-bpf support for Android. Requires experimental kernel
 // support. <http://crbug.com/166704>
 const char kEnableSeccompFilterSandbox[] =
     "enable-seccomp-filter-sandbox";
 
 // Enables the Skia benchmarking extension
@@ skipping 575 matching lines @@
 // Windows Vista and later.
 const char kTraceExportEventsToETW[] = "trace-export-events-to-etw";
 #endif
 
 // Enables the use of NPAPI plugins.
 const char kEnableNpapi[]                   = "enable-npapi";
 
 // Don't dump stuff here, follow the same order as the header.
 
 }  // namespace switches