Create an invisible window during login so that
mouse can move between displays.

Added NoSessionAshTestBase for tests that should run before
a user logs in.

BUG=266987
TEST=covered by test
[email protected]

Review URL: https://chromiumcodereview.appspot.com/21519002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@216184 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/ash/root_window_controller.h b/ash/root_window_controller.h
index 05ab29f..bbf29ce 100644
--- a/ash/root_window_controller.h
+++ b/ash/root_window_controller.h
@@ -241,6 +241,13 @@
   // The shelf for managing the launcher and the status widget.
   scoped_ptr<ShelfWidget> shelf_;
 
+  // An invisible/empty window used as a event target for
+  // |MouseCursorEventFilter| before a user logs in.
+  // (crbug.com/266987)
+  // Its container is |LockScreenBackgroundContainer| and
+  // this must be deleted before the container is deleted.
+  scoped_ptr<aura::Window> mouse_event_target_;
+
   // Manages layout of docked windows. Owned by DockedContainer.
   DockedWindowLayoutManager* docked_layout_manager_;