Eliminate ash::internal namespace

ash/shell_window_ids.h

Index: ash/shell_window_ids.h
diff --git a/ash/shell_window_ids.h b/ash/shell_window_ids.h
index aedc8b50a992ff55f12761648a1d297ea9bb67c7..a4bd516c4eb780a65f37b6f767236308aad25a73 100644
--- a/ash/shell_window_ids.h
+++ b/ash/shell_window_ids.h
@@ -9,10 +9,6 @@
 
 namespace ash {
 
-// TODO: we're using this in random places outside of ash, it shouldn't be in
-// internal.
-namespace internal {
-
 // A higher-level container that holds all of the containers stacked below
 // kShellWindowId_LockScreenContainer.  Only used by PowerButtonController for
 // animating lower-level containers.
@@ -110,8 +106,6 @@ const int kShellWindowId_MouseCursorContainer = 25;
 // The topmost container, used for power off animation.
 const int kShellWindowId_PowerButtonAnimationContainer = 26;
 
-}  // namespace internal
-
 }  // namespace ash