chromeos: Converts WorkspaceLayoutManager to aura::LayoutManager

ash/wm/mru_window_tracker.cc

Index: ash/wm/mru_window_tracker.cc
diff --git a/ash/wm/mru_window_tracker.cc b/ash/wm/mru_window_tracker.cc
index dcc8ad49290b9aa8c65d05299f4db3fa89d1c930..c44c1755fc5b0be63623e561145cff224f408033 100644
--- a/ash/wm/mru_window_tracker.cc
+++ b/ash/wm/mru_window_tracker.cc
@@ -76,7 +76,8 @@ MruWindowTracker::WindowList BuildWindowListInternal(
     for (auto ix = mru_windows->rbegin(); ix != mru_windows->rend(); ++ix) {
       // Exclude windows in non-switchable containers and those which cannot
       // be activated.
-      if (!wm::IsSwitchableContainer((*ix)->GetParent()) ||
+      if (((*ix)->GetParent() &&
+           !wm::IsSwitchableContainer((*ix)->GetParent()->aura_window())) ||
           !should_include_window_predicate.Run(*ix)) {
         continue;
       }