Converts overview to use common ash types

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 88636671a2a263ac4741564b57b1181d85baf21a..2b86e2e0a791078d4006a029d962722d44c92df1 100644
--- a/ash/shell_window_ids.h
+++ b/ash/shell_window_ids.h
@@ -93,8 +93,8 @@ const int kShellWindowId_ImeWindowParentContainer = 18;
 const int kShellWindowId_SettingBubbleContainer = 21;
 
 // The container for special components overlaid onscreen, such as the
-// region selector for partial screenshots.
-const int kShellWindowId_OverlayContainer = 22;
+// region selector for partial screenshots. Defined in wm_shell_window_ids.
+// const int kShellWindowId_OverlayContainer = 22;
 
 // ID of the window created by PhantomWindowController or DragWindowController.
 // Defined in wm_shell_window_ids.
@@ -180,6 +180,12 @@ static_assert((kShellWindowId_DragImageAndTooltipContainer - 1 ==
                    kShellWindowId_SettingBubbleContainer),
               "drag-image-and-tooltip between menu and settings-bubble");
 
+static_assert((kShellWindowId_OverlayContainer - 1 ==
+               kShellWindowId_SettingBubbleContainer) &&
+                  (kShellWindowId_OverlayContainer + 1 ==
+                   kShellWindowId_PhantomWindow),
+              "overlay between settings-bubble and phanton");

[James Cook, 2016/05/27 00:02:50]

nit: phanton -> phantom

[sky, 2016/05/27 03:18:03]

Done.

+
 static_assert((kShellWindowId_PhantomWindow - 1 ==
                kShellWindowId_OverlayContainer) &&
                   (kShellWindowId_PhantomWindow + 1 ==