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

content/shell/app/blink_test_platform_support_mac.mm

 // Copyright 2013 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 "base/command_line.h"
 #include "base/logging.h"
 #include "base/mac/bundle_locations.h"
 #include "base/path_service.h"
 #include "content/public/common/content_switches.h"
 #include "content/shell/app/blink_test_platform_support.h"
@@ skipping 69 matching lines @@
                                          &errors)) {
     DLOG(FATAL) << "Fail to activate fonts.";
     CFRelease(errors);
   }
 
   // Add <app bundle's parent dir>/plugins to the plugin path so we can load
   // test plugins.
   base::FilePath plugins_dir;
   PathService::Get(base::DIR_EXE, &plugins_dir);
   plugins_dir = plugins_dir.AppendASCII("../../../plugins");
-  CommandLine& command_line = *CommandLine::ForCurrentProcess();
+  base::CommandLine& command_line = *base::CommandLine::ForCurrentProcess();
   command_line.AppendSwitchPath(switches::kExtraPluginDir, plugins_dir);
 
   return true;
 }
 
 }  // namespace