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

chrome/browser/history/history_browsertest.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 <vector>
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/message_loop/message_loop.h"
 #include "base/prefs/pref_service.h"
@@ skipping 42 matching lines @@
  private:
   ~WaitForHistoryTask() override {}
 
   DISALLOW_COPY_AND_ASSIGN(WaitForHistoryTask);
 };
 
 }  // namespace
 
 class HistoryBrowserTest : public InProcessBrowserTest {
  protected:
-  void SetUpCommandLine(CommandLine* command_line) override {
+  void SetUpCommandLine(base::CommandLine* command_line) override {
     command_line->AppendSwitch(switches::kEnableFileCookies);
   }
 
   PrefService* GetPrefs() {
     return GetProfile()->GetPrefs();
   }
 
   Profile* GetProfile() {
     return browser()->profile();
   }
@@ skipping 426 matching lines @@
 
   content::WebContents* active_web_contents =
       browser()->tab_strip_model()->GetActiveWebContents();
   ASSERT_EQ(web_contents, active_web_contents);
   ASSERT_EQ(history_url, active_web_contents->GetURL());
 
   content::WebContents* second_tab =
       browser()->tab_strip_model()->GetWebContentsAt(1);
   ASSERT_NE(history_url, second_tab->GetURL());
 }