wm: Remove crashing DCHECK in workspace_layout_manager.cc.

This crashes now with async window state changing ARC apps. Since
DCHECK, remove. Also WindowState::Unminimze is pretty stable.

Test: none
Change-Id: I1786fe81a36e73b3c94b9fd4c40bcf7f64f93a51
Fixed: 1067240
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2210727
Commit-Queue: Sammie Quon <sammiequon@chromium.org>
Reviewed-by: Xiaoqian Dai <xdai@chromium.org>
Cr-Commit-Position: refs/heads/master@{#770720}

ash/wm/workspace/workspace_layout_manager.cc

@@ -350,7 +350,6 @@ void WorkspaceLayoutManager::OnWindowActivating(ActivationReason reason,
   if (window_state && window_state->IsMinimized() &&
       !gaining_active->IsVisible()) {
     window_state->Unminimize();
-    DCHECK(!window_state->IsMinimized());
   }
 }