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

chrome/browser/chromeos/login/screenshot_testing/screenshot_tester.cc

 // Copyright 2014 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/chromeos/login/screenshot_testing/screenshot_tester.h"
 
 #include "ash/shell.h"
 #include "base/command_line.h"
 #include "base/files/file_util.h"
 #include "chrome/browser/chromeos/login/screenshot_testing/SkDiffPixelsMetric.h"
@@ skipping 30 matching lines @@
 ScreenshotTester::~ScreenshotTester() {
 }
 
 ScreenshotTester::Result::Result() {
 }
 
 ScreenshotTester::Result::~Result() {
 }
 
 bool ScreenshotTester::TryInitialize() {
-  CommandLine& command_line = *CommandLine::ForCurrentProcess();
+  base::CommandLine& command_line = *base::CommandLine::ForCurrentProcess();
   if (!command_line.HasSwitch(switches::kEnableScreenshotTestingWithMode))
     return false;
 
   std::string mode = command_line.GetSwitchValueASCII(
       switches::kEnableScreenshotTestingWithMode);
   CHECK(mode == kUpdateMode || mode == kTestMode || mode == kPdiffTestMode)
       << "Invalid mode for screenshot testing: " << mode;
 
   CHECK(command_line.HasSwitch(chromeos::switches::kGoldenScreenshotsDir))
       << "No directory with golden screenshots specified, use "
@@ skipping 281 matching lines @@
 
   ScreenshotTester::Result testing_result;
   testing_result.similarity = result.result;
   testing_result.screenshots_match =
       (result.result == SkImageDiffer::RESULT_CORRECT);
 
   return testing_result;
 }
 
 }  // namespace chromeos