[exp] Always use the Display bounds.

ash/screen_util.cc

Index: ash/screen_util.cc
diff --git a/ash/screen_util.cc b/ash/screen_util.cc
index c27d896e52cb2e107fb31b7c1515aba754dc14f5..a858e4fb4a14c1dbf07c5814ee115d48a9964b40 100644
--- a/ash/screen_util.cc
+++ b/ash/screen_util.cc
@@ -65,7 +65,9 @@ gfx::Rect ScreenUtil::GetShelfDisplayBoundsInRoot(aura::Window* window) {
     size.Scale(scale, scale);
     return gfx::Rect(gfx::ToCeiledSize(size));
   } else {
-    return window->GetRootWindow()->bounds();
+    gfx::Display display =
+        gfx::Screen::GetScreen()->GetDisplayNearestWindow(window);
+    return gfx::Rect(display.size());
   }
 }