Remove unnecessary #includes in system_tray.cc and tray_user_unittest.cc.

After the landing https://codereview.chromium.org/184113005,
system_tray.cc and tray_user_unittest.cc don't need the command line
switch related headers anymore. So we can remove these.

BUG=348133

Review URL: https://codereview.chromium.org/338133002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@277894 0039d316-1c4b-4281-b951-d872f2087c98

ash/system/tray/system_tray.cc

@@ -26,7 +26,6 @@
 #include "ash/system/user/tray_user.h"
 #include "ash/system/user/tray_user_separator.h"
 #include "ash/system/web_notification/web_notification_tray.h"
-#include "base/command_line.h"
 #include "base/logging.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/timer/timer.h"

ash/system/user/tray_user_unittest.cc

@@ -4,7 +4,6 @@
 
 #include <vector>
 
-#include "ash/ash_switches.h"
 #include "ash/root_window_controller.h"
 #include "ash/session/user_info.h"
 #include "ash/shelf/shelf_layout_manager.h"
@@ -17,7 +16,6 @@
 #include "ash/test/ash_test_base.h"
 #include "ash/test/test_session_state_delegate.h"
 #include "ash/test/test_shell_delegate.h"
-#include "base/command_line.h"
 #include "ui/aura/test/event_generator.h"
 #include "ui/gfx/animation/animation_container_element.h"
 #include "ui/views/view.h"