Do not register invalid layout

ash/display/display_layout.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ash/display/display_layout.h"
 
 #include <sstream>
 
 #include "ash/ash_switches.h"
 #include "ash/display/display_pref_util.h"
@@ skipping 210 matching lines @@
   converter->RegisterCustomField<int64_t>(
       kPrimaryIdKey, &DisplayLayout::primary_id, &GetDisplayIdFromString);
   converter->RegisterRepeatedMessage<DisplayPlacement>(
       kDisplayPlacementKey, &DisplayLayout::placement_list);
 }
 
 // static
 bool DisplayLayout::Validate(const DisplayIdList& list,
                              const DisplayLayout& layout) {
   // The primary display should be in the list.
-  DCHECK(IsIdInList(layout.primary_id, list));
+  if (!IsIdInList(layout.primary_id, list))
+    return false;
 
   // Unified mode, or mirror mode switched from unified mode,
   // may not have the placement yet.
   if (layout.placement_list.size() == 0u)
     return true;
 
   bool has_primary_as_parent = false;
   int64_t id = 0;
 
   for (const auto* placement : layout.placement_list) {
@@ skipping 70 matching lines @@
     s << (added ? "),(" : " [(");
     s << placement->ToString();
     added = true;
   }
   if (added)
     s << ")]";
   return s.str();
 }
 
 }  // namespace ash