Fix Task Manager being always-on-top.

This was broken by the new window level machinery CL.

BUG=988214
TEST=as in bug

Change-Id: Ifd6c132e160d6a2e29aa663ecaf87b2330322c61
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1723749Reviewed-by: Ahmed Fakhry <afakhry@chromium.org>
Commit-Queue: Avi Drissman <avi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#681864}

chrome/browser/ui/views/task_manager_view.cc

@@ -357,7 +357,9 @@ void TaskManagerView::Init() {
 
 void TaskManagerView::InitAlwaysOnTopState() {
   RetrieveSavedAlwaysOnTopState();
-  GetWidget()->SetZOrderLevel(ui::ZOrderLevel::kFloatingWindow);
+  GetWidget()->SetZOrderLevel(is_always_on_top_
+                                  ? ui::ZOrderLevel::kFloatingWindow
+                                  : ui::ZOrderLevel::kNormal);
 }
 
 void TaskManagerView::ActivateSelectedTab() {