Add TODO link to the display-id being invalid bug.

Bug: 1068018, 1131071
Change-Id: I4261a55eaf5ef4eae3e2ac6ff6402351a278836b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2429824Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Commit-Queue: Xiaoqian Dai <xdai@chromium.org>
Cr-Commit-Position: refs/heads/master@{#810327}

ash/wm/drag_window_resizer.cc

@@ -143,6 +143,11 @@ void DragWindowResizer::EndDragImpl() {
   // Adjust the size and position so that it doesn't exceed the size of work
   // area.
   display::Display dst_display;
+  // TODO(crbug.com/1131071): It's possible that |dst_display_id| returned from
+  // CursorManager::GetDisplay().id() is an invalid display id thus
+  // |dst_display| may be invalid as well. This may cause crash later. To avoid
+  // crash, we early return here. However, |dst_display_id| should never be
+  // invalid.
   if (!screen->GetDisplayWithDisplayId(dst_display_id, &dst_display))
     return;
   const gfx::Size& size = dst_display.work_area().size();