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

tools/gn/command_check.cc

 // Copyright 2014 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/strings/stringprintf.h"
 #include "tools/gn/commands.h"
 #include "tools/gn/header_checker.h"
 #include "tools/gn/setup.h"
 #include "tools/gn/standard_out.h"
@@ skipping 74 matching lines @@
     if (setup->check_patterns()) {
       FilterTargetsByPatterns(all_targets, *setup->check_patterns(),
                               &targets_to_check);
       filtered_by_build_config = targets_to_check.size() != all_targets.size();
     } else {
       // No global filter, check everything.
       targets_to_check = all_targets;
     }
   }
 
-  const CommandLine* cmdline = CommandLine::ForCurrentProcess();
+  const base::CommandLine* cmdline = base::CommandLine::ForCurrentProcess();
   bool force = cmdline->HasSwitch("force");
 
   if (!CheckPublicHeaders(&setup->build_settings(), all_targets,
                           targets_to_check, force))
     return 1;
 
   if (!base::CommandLine::ForCurrentProcess()->HasSwitch(switches::kQuiet)) {
     if (filtered_by_build_config) {
       // Tell the user about the implicit filtering since this is obscure.
       OutputString(base::StringPrintf(
@@ skipping 33 matching lines @@
     for (const auto& pattern : filter) {
       if (pattern.Matches(target->label())) {
         output->push_back(target);
         break;
       }
     }
   }
 }
 
 }  // namespace commands