Exempt status bubble windows from status bar darkening

ash/wm/property_util.h

Index: ash/wm/property_util.h
diff --git a/ash/wm/property_util.h b/ash/wm/property_util.h
index bb8e4318f2230a4ecf08ad92f793ed3044d91e65..dde033534979de0953dcf55d9ff1ea7824301bb4 100644
--- a/ash/wm/property_util.h
+++ b/ash/wm/property_util.h
@@ -47,6 +47,11 @@ enum WindowPersistsAcrossAllWorkspacesType {
   WINDOW_PERSISTS_ACROSS_ALL_WORKSPACES_VALUE_YES,
 };
 
+// Sets whether |window| is ignored when determining whether the shelf should
+// be darkened when overlapped.
+ASH_EXPORT void SetIgnoredByShelf(aura::Window* window, bool value);
+ASH_EXPORT bool GetIgnoredByShelf(aura::Window* window);
+
 // Sets whether the specified window is tracked by workspace code. Default is
 // true. If set to false the workspace does not switch the current workspace,
 // nor does it attempt to impose constraints on the bounds of the window. This