Reduce unnecessary operations in perpareSurface

- If the window doesn't have surface, skip updating position
  and scale. Usually the no surface windows could be
  NotificationShade, EdgeBackGestureHandler, SecondaryHomeHandle,
  InputMethod, ScreenDecorOverlay, ScreenDecorOverlayBottom,
  ShellDropTarget.
- Only calculate dim bounds if the dim layer is showing.

Bug: 159103089
Test: DimmerTests CtsWindowManagerDeviceTestCases

Change-Id: I090675457cb465dfb4e656feb1dc272d00ebb45e