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

chrome/browser/locale_tests_browsertest.cc

Index: chrome/browser/locale_tests_browsertest.cc
diff --git a/chrome/browser/locale_tests_browsertest.cc b/chrome/browser/locale_tests_browsertest.cc
index ba2f26ebcba294ba66090e6863f8d480ba56bd5b..6c57279e081a23288c390397a17805537489220c 100644
--- a/chrome/browser/locale_tests_browsertest.cc
+++ b/chrome/browser/locale_tests_browsertest.cc
@@ -69,7 +69,7 @@ class LocaleTestBase : public InProcessBrowserTest {
   explicit LocaleTestBase(const char* locale) : locale_(locale) {
   }
 
-  void SetUpCommandLine(CommandLine* command_line) override {
+  void SetUpCommandLine(base::CommandLine* command_line) override {
     command_line->AppendSwitchASCII(switches::kLang, locale_.locale());
   }