Eliminate ash::internal namespace

ash/first_run/desktop_cleaner.cc

Index: ash/first_run/desktop_cleaner.cc
diff --git a/ash/first_run/desktop_cleaner.cc b/ash/first_run/desktop_cleaner.cc
index 8008cdaed598387c51d7f3d885e30aba76452bbc..d388e18f33e1a56c49e26308bf70e1dd1dd8e908 100644
--- a/ash/first_run/desktop_cleaner.cc
+++ b/ash/first_run/desktop_cleaner.cc
@@ -14,8 +14,6 @@
 #include "ui/message_center/notification_blocker.h"
 
 namespace ash {
-namespace internal {
-
 namespace {
 
 const int kContainerIdsToHide[] = {
@@ -114,6 +112,5 @@ std::vector<int> DesktopCleaner::GetContainersToHideForTest() {
                           kContainerIdsToHide + arraysize(kContainerIdsToHide));
 }
 
-}  // namespace internal
 }  // namespace ash