Eliminate ash::internal namespace

ash/wm/maximize_mode/workspace_backdrop_delegate.cc

Index: ash/wm/maximize_mode/workspace_backdrop_delegate.cc
diff --git a/ash/wm/maximize_mode/workspace_backdrop_delegate.cc b/ash/wm/maximize_mode/workspace_backdrop_delegate.cc
index 455f3626eaeace8d0141fe8b4f3e61087d5431fb..0b7fc0133f0d95fc0f349c29823cff4b31457063 100644
--- a/ash/wm/maximize_mode/workspace_backdrop_delegate.cc
+++ b/ash/wm/maximize_mode/workspace_backdrop_delegate.cc
@@ -16,9 +16,6 @@
 #include "ui/wm/core/window_util.h"
 
 namespace ash {
-
-namespace internal {
-
 namespace {
 
 // The opacity of the backdrop.
@@ -149,5 +146,4 @@ void WorkspaceBackdropDelegate::Show() {
   background_->GetNativeView()->layer()->SetOpacity(kBackdropOpacity);
 }
 
-}  // namespace internal
 }  // namespace ash