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

chrome/browser/apps/app_shim/app_shim_quit_interactive_uitest_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.
 
 // Tests behavior when quitting apps with app shims.
 
 #import <Cocoa/Cocoa.h>
 #include <vector>
 
 #include "apps/switches.h"
@@ skipping 67 matching lines @@
                            APP_SHIM_LAUNCH_REGISTER_ONLY,
                            std::vector<base::FilePath>());
     EXPECT_EQ(host_.get(), handler_->FindHost(profile(), extension_id_));
 
     // Focus the app window.
     NSWindow* window = [[NSApp windows] objectAtIndex:0];
     EXPECT_TRUE(ui_test_utils::ShowAndFocusNativeWindow(window));
     content::RunAllPendingInMessageLoop();
   }
 
-  void SetUpCommandLine(CommandLine* command_line) override {
+  void SetUpCommandLine(base::CommandLine* command_line) override {
     PlatformAppBrowserTest::SetUpCommandLine(command_line);
     // Simulate an app shim initiated launch, i.e. launch app but not browser.
     app_path_ = test_data_dir_
         .AppendASCII("platform_apps")
         .AppendASCII("minimal");
     command_line->AppendSwitchNative(apps::kLoadAndLaunchApp,
                                      app_path_.value());
     command_line->AppendSwitch(switches::kSilentLaunch);
   }
 
@@ skipping 20 matching lines @@
             atStart:NO];
 
   // This will time out if the event above does not terminate Chrome.
   content::RunMessageLoop();
 
   EXPECT_FALSE(handler_->FindHost(profile(), extension_id_));
   EXPECT_TRUE(browser_shutdown::IsTryingToQuit());
 }
 
 }  // namespace apps