Add command line switch to enable region based columns.

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 {
 
 // By default, file:// URIs cannot read other file:// URIs. This is an
 // override for developers who need the old behavior for testing.
@@ skipping 304 matching lines @@
 // Enables device motion events.
 const char kEnableDeviceMotion[]            = "enable-device-motion";
 
 // Enables restarting interrupted downloads.
 const char kEnableDownloadResumption[]      = "enable-download-resumption";
 
 // Enables WebKit features that are in development.
 const char kEnableExperimentalWebKitFeatures[] =
     "enable-experimental-webkit-features";
 
+// Enables the CSS multicol implementation that uses the regions implementation.
+const char kEnableRegionBasedColumns[] =
+    "enable-region-based-columns";
+
 // Disables the threaded HTML parser in WebKit
 const char kDisableThreadedHTMLParser[]     = "disable-threaded-html-parser";
 
 // By default, a page is laid out to fill the entire width of the window.
 // This flag fixes the layout of the page to a default of 980 CSS pixels,
 // or to a specified width and height using --enable-fixed-layout=w,h
 const char kEnableFixedLayout[]             = "enable-fixed-layout";
 
 // Disable the JavaScript Full Screen API.
 const char kDisableFullScreen[]             = "disable-fullscreen";
@@ skipping 518 matching lines @@
 // Forward overscroll event data from the renderer to the browser.
 const char kEnableOverscrollNotifications[] = "enable-overscroll-notifications";
 
 // Enables 'image/webp' accept header for image requests.
 const char kEnableWebPInAcceptHeader[] = "enable-webp-in-accept-header";
 
 // Enables WebGL extensions not yet approved by the community.
 const char kEnableWebGLDraftExtensions[] = "enable-webgl-draft-extensions";
 
 }  // namespace switches