Check DisplayItemCient aliveness in cached subsequences

third_party/WebKit/Source/platform/graphics/paint/PaintController.h

 // Copyright 2014 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.
 
 #ifndef PaintController_h
 #define PaintController_h
 
 #include "platform/PlatformExport.h"
 #include "platform/RuntimeEnabledFeatures.h"
 #include "platform/geometry/IntRect.h"
@@ skipping 221 matching lines @@
     // Record the debug names of invalidated clients for assertion and debugging.
     Vector<String> m_invalidations;
 
     // This is used to check duplicated ids during add(). We could also check
     // during commitNewDisplayItems(), but checking during add() helps developer
     // easily find where the duplicated ids are from.
     DisplayItemIndicesByClientMap m_newDisplayItemIndicesByClient;
 #endif
 
     DisplayItemCacheGeneration m_currentCacheGeneration;
+
+#if CHECK_DISPLAY_ITEM_CLIENT_ALIVENESS
+    // A stack recording subsequence clients that are currently painting.
+    Vector<const DisplayItemClient*> m_currentSubsequenceClients;
+#endif
 };
 
 } // namespace blink
 
 #endif // PaintController_h