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

chrome/browser/extensions/api/cloud_print_private/cloud_print_private_apitest.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 "chrome/browser/extensions/api/cloud_print_private/cloud_print_private_api.h"
 
 #include "base/strings/stringprintf.h"
 #include "chrome/browser/extensions/extension_apitest.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/common/extensions/api/cloud_print_private.h"
 #include "components/cloud_devices/common/cloud_devices_switches.h"
 #include "net/dns/mock_host_resolver.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 using ::testing::Eq;
 using ::testing::Property;
 using ::testing::Return;
 using ::testing::_;
 
 // A base class for tests below.
 class ExtensionCloudPrintPrivateApiTest : public ExtensionApiTest {
  public:
-  void SetUpCommandLine(CommandLine* command_line) override {
+  void SetUpCommandLine(base::CommandLine* command_line) override {
     ExtensionApiTest::SetUpCommandLine(command_line);
     command_line->AppendSwitchASCII(
         switches::kCloudPrintURL,
         "http://www.cloudprintapp.com/files/extensions/api_test/"
         "cloud_print_private");
   }
 
   void SetUpInProcessBrowserTestFixture() override {
     // Start up the test server and get us ready for calling the install
     // API functions.
@@ skipping 78 matching lines @@
 
   // Run this as a hosted app. Since we have overridden the cloud print service
   // URL in the command line, this URL should match the web extent for our
   // cloud print component app and it should work.
   GURL page_url = GetTestServerURL(
       "enable_chrome_connector/cloud_print_success_tests.html");
   ASSERT_TRUE(RunPageTest(page_url.spec()));
 }
 
 #endif  // !defined(OS_CHROMEOS)