Eliminate ash::internal namespace

ash/drag_drop/drag_drop_controller.cc

Index: ash/drag_drop/drag_drop_controller.cc
diff --git a/ash/drag_drop/drag_drop_controller.cc b/ash/drag_drop/drag_drop_controller.cc
index cc8d96b00230a893dcb6002eb153a0556148b72f..4a2603f05309c9bef34dc3df07db606225f6e5a9 100644
--- a/ash/drag_drop/drag_drop_controller.cc
+++ b/ash/drag_drop/drag_drop_controller.cc
@@ -31,9 +31,8 @@
 #include "ui/wm/public/drag_drop_delegate.h"
 
 namespace ash {
-namespace internal {
-
 namespace {
+
 // The duration of the drag cancel animation in millisecond.
 const int kCancelAnimationDuration = 250;
 const int kTouchCancelAnimationDuration = 20;
@@ -560,5 +559,4 @@ void DragDropController::Cleanup() {
   drag_drop_tracker_.Pass();
 }
 
-}  // namespace internal
 }  // namespace ash