Add asserts

Signed-off-by: Yan Avlasov <yavlasov@google.com>

source/common/http/filter_manager.cc

@@ -541,6 +541,8 @@ void FilterManager::decodeHeaders(ActiveStreamDecoderFilter* filter, RequestHead
       commonDecodePrefix(filter, FilterIterationStartState::AlwaysStartFromNext);
   std::list<ActiveStreamDecoderFilterPtr>::iterator continue_data_entry = decoder_filters_.end();
   bool terminal_filter_decoded_end_stream = false;
+  ASSERT(!state_.decoder_filter_chain_complete_ || entry == decoder_filters_.end() ||
+         (*entry)->end_stream_);
 
   for (; entry != decoder_filters_.end(); entry++) {
     ASSERT(!(state_.filter_call_state_ & FilterCallState::DecodeHeaders));
@@ -650,6 +652,8 @@ void FilterManager::decodeData(ActiveStreamDecoderFilter* filter, Buffer::Instan
   std::list<ActiveStreamDecoderFilterPtr>::iterator entry =
       commonDecodePrefix(filter, filter_iteration_start_state);
   bool terminal_filter_decoded_end_stream = false;
+  ASSERT(!state_.decoder_filter_chain_complete_ || entry == decoder_filters_.end() ||
+         (*entry)->end_stream_);
 
   for (; entry != decoder_filters_.end(); entry++) {
     // If the filter pointed by entry has stopped for all frame types, return now.
@@ -799,6 +803,7 @@ void FilterManager::decodeTrailers(ActiveStreamDecoderFilter* filter, RequestTra
   std::list<ActiveStreamDecoderFilterPtr>::iterator entry =
       commonDecodePrefix(filter, FilterIterationStartState::CanStartFromCurrent);
   bool terminal_filter_reached = false;
+  ASSERT(!state_.decoder_filter_chain_complete_ || entry == decoder_filters_.end());
 
   for (; entry != decoder_filters_.end(); entry++) {
     // If the filter pointed by entry has stopped for all frame type, return now.