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

chrome/browser/extensions/api/media_galleries_private/media_galleries_watch_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.
 //
 // MediaGalleriesPrivate gallery watch API browser tests.
 
 #include "base/files/file_path.h"
 #include "base/files/file_path_watcher.h"
 #include "base/files/file_util.h"
 #include "base/run_loop.h"
@@ skipping 59 matching lines @@
 class MediaGalleriesPrivateGalleryWatchApiTest : public ExtensionApiTest {
  public:
   MediaGalleriesPrivateGalleryWatchApiTest()
       : extension_(NULL),
         background_host_(NULL) {
   }
   ~MediaGalleriesPrivateGalleryWatchApiTest() override {}
 
  protected:
   // ExtensionApiTest overrides.
-  void SetUpCommandLine(CommandLine* command_line) override {
+  void SetUpCommandLine(base::CommandLine* command_line) override {
     ExtensionApiTest::SetUpCommandLine(command_line);
     command_line->AppendSwitchASCII(
         extensions::switches::kWhitelistedExtensionID,
         kTestExtensionId);
   }
   void SetUpOnMainThread() override {
     ExtensionApiTest::SetUpOnMainThread();
     ensure_media_directories_exists_.reset(new EnsureMediaDirectoriesExists);
     extension_ = LoadExtension(test_data_dir_.AppendASCII(kTestExtensionPath));
     GetBackgroundHostForTestExtension();
@@ skipping 242 matching lines @@
   // Remove all gallery watchers.
   ExecuteCmdAndCheckReply(kRemoveAllGalleryWatchCmd, kRemoveAllGalleryWatchOK);
 
   // Gallery watchers removed. chrome.mediaGalleriesPrivate.getAllGalleryWatch
   // should return an empty list.
   ExtensionTestMessageListener final_get_all_check_finished(
       kNoGalleryWatchesInstalled, false  /* no reply */);
   ExecuteCmdAndCheckReply(kGetAllWatchedGalleryIdsCmd, kGetAllGalleryWatchOK);
   EXPECT_TRUE(final_get_all_check_finished.WaitUntilSatisfied());
 }