Moves DefaultContainer and PanelContainer to wm_shell_window_ids

ash/wm/common/wm_shell_window_ids.h

Index: ash/wm/common/wm_shell_window_ids.h
diff --git a/ash/wm/common/wm_shell_window_ids.h b/ash/wm/common/wm_shell_window_ids.h
index 92c5460facb03f684c7490b968cbb400bca63e0e..a863423f3c5e039c90ce1c91c34eb59d675c5cc6 100644
--- a/ash/wm/common/wm_shell_window_ids.h
+++ b/ash/wm/common/wm_shell_window_ids.h
@@ -13,8 +13,18 @@
 // TODO(sky): move this into wm namespace.
 namespace ash {
 
+// NOTE: while the value of these is not necessarily important, the ordering
+// is and is enforced in ash/shell_window_ids.h.
+
+// The container for standard top-level windows.
+const int kShellWindowId_DefaultContainer = 6;
+
+// The container for windows docked to either side of the desktop.
 const int kShellWindowId_DockedContainer = 8;
 
+// The container for panel windows.
+const int kShellWindowId_PanelContainer = 11;
+
 }  // namespace ash
 
 #endif  // ASH_WM_COMMON_WM_SHELL_WINDOW_IDS_H_