Always pair begin and end subsequence calls

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

 // 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.
 
 #include "platform/graphics/paint/PaintController.h"
 
 #include "platform/graphics/GraphicsLayer.h"
 #include "platform/graphics/paint/DrawingDisplayItem.h"
 #include "platform/instrumentation/tracing/TraceEvent.h"
 #include "platform/wtf/AutoReset.h"
@@ skipping 522 matching lines @@
 
   current_cache_generation_ =
       DisplayItemClient::CacheGenerationOrInvalidationReason::Next();
 
   new_cached_subsequences_.Swap(current_cached_subsequences_);
   new_cached_subsequences_.Clear();
   for (auto& item : current_cached_subsequences_) {
     item.key->SetDisplayItemsCached(current_cache_generation_);
 #if CHECK_DISPLAY_ITEM_CLIENT_ALIVENESS
     DisplayItemClient::EndShouldKeepAliveAllClients(item.key);
+    DCHECK(current_subsequence_clients_.IsEmpty());
 #endif
   }
 
   Vector<const DisplayItemClient*> skipped_cache_clients;
   for (const auto& item : new_display_item_list_) {
     // No reason to continue the analysis once we have a veto.
     if (gpu_analyzer.suitableForGpuRasterization())
       item.AnalyzeForGpuRasterization(gpu_analyzer);
 
     // TODO(wkorman): Only compute and append visual rect for drawings.
@@ skipping 371 matching lines @@
               show_paint_records
                   ? (DisplayItemList::JsonOptions::kShowPaintRecords |
                      DisplayItemList::JsonOptions::kShowClientDebugName)
                   : DisplayItemList::JsonOptions::kShowClientDebugName)
           ->ToPrettyJSONString()
           .Utf8()
           .Data());
 }
 
 }  // namespace blink