Drop superfluous check at ShadowController::Impl::HandlePossibleShadowVisibilityChange()

  if (bleh) {
    (...)
  } else if (!bleh) {
    (...)
  }

BUG=None
R=sky@chromium.org

Change-Id: I7e303732499e1cfc77a23e08186a921612cbff27
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2346608
Auto-Submit: Antonio Gomes (GMT-4) <tonikitoo@igalia.com>
Commit-Queue: Scott Violet <sky@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#796874}

ui/wm/core/shadow_controller.cc

@@ -264,7 +264,7 @@ void ShadowController::Impl::HandlePossibleShadowVisibilityChange(
   if (shadow) {
     shadow->SetElevation(GetShadowElevationForActiveState(window));
     shadow->layer()->SetVisible(should_show);
-  } else if (should_show && !shadow) {
+  } else if (should_show) {
     CreateShadowForWindow(window);
   }
 }