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

chrome/browser/prefs/chrome_pref_service_factory.cc

Index: chrome/browser/prefs/chrome_pref_service_factory.cc
diff --git a/chrome/browser/prefs/chrome_pref_service_factory.cc b/chrome/browser/prefs/chrome_pref_service_factory.cc
index 5b626ceadf9626ba22dd901f335bcf6b6fcb86ac..e82f472ed177b7f91f4242108f9dd14283ceb7d8 100644
--- a/chrome/browser/prefs/chrome_pref_service_factory.cc
+++ b/chrome/browser/prefs/chrome_pref_service_factory.cc
@@ -397,9 +397,8 @@ void PrepareFactory(
 
   factory->set_async(async);
   factory->set_extension_prefs(extension_prefs);
-  factory->set_command_line_prefs(
-      make_scoped_refptr(
-          new CommandLinePrefStore(CommandLine::ForCurrentProcess())));
+  factory->set_command_line_prefs(make_scoped_refptr(
+      new CommandLinePrefStore(base::CommandLine::ForCurrentProcess())));
   factory->set_read_error_callback(base::Bind(&HandleReadError));
   factory->set_user_prefs(user_pref_store);
 }