Make callers of CommandLine use it via the base:: namespace.

chrome/browser/fullscreen_mac.mm

 // Copyright (c) 2011 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.
 
 #import "chrome/browser/fullscreen.h"
 
 #import <Cocoa/Cocoa.h>
 
 #include "base/command_line.h"
 #include "base/mac/mac_util.h"
@@ skipping 22 matching lines @@
   if (options & NSApplicationPresentationFullScreen)
     return true;
 
   return false;
 }
 
 namespace chrome {
 namespace mac {
 
 bool SupportsSystemFullscreen() {
-  const CommandLine* command_line = CommandLine::ForCurrentProcess();
+  const base::CommandLine* command_line =
+      base::CommandLine::ForCurrentProcess();
   if (command_line->HasSwitch(switches::kDisableSystemFullscreenForTesting))
     return false;
 
   return base::mac::IsOSLionOrLater();
 }
 
 }  // namespace mac
 }  // namespace chrome