Make QuicSpdyStream::OnStreamHeaderList() return void.

Only QuicSpdyStream::OnHeadersFrameEnd() cares about the return value.
When blocked encoding is implemented, the return value will be
considered and passed back to HttpDecoder in the synchronous case, but
will be ignored in the async case, where OnStreamHeaderList() will be
called not from inside an HttpDecoder::ProcessInput() call.

gfe-relnote: n/a, change to QUIC v99-only code path.
PiperOrigin-RevId: 255242560
Change-Id: I4ef67a7f8b0926830e12a3da0f6317b32db951e3
diff --git a/quic/core/http/quic_spdy_stream.cc b/quic/core/http/quic_spdy_stream.cc
index c42f39c..6db96fa 100644
--- a/quic/core/http/quic_spdy_stream.cc
+++ b/quic/core/http/quic_spdy_stream.cc
@@ -469,7 +469,7 @@
   SetPriority(priority);
 }
 
-bool QuicSpdyStream::OnStreamHeaderList(bool fin,
+void QuicSpdyStream::OnStreamHeaderList(bool fin,
                                         size_t frame_len,
                                         const QuicHeaderList& header_list) {
   // TODO(b/134706391): remove |fin| argument.
@@ -482,7 +482,7 @@
   if (header_list.empty()) {
     OnHeadersTooLarge();
     if (IsDoneReading()) {
-      return false;
+      return;
     }
   }
   if (!headers_decompressed_) {
@@ -490,7 +490,6 @@
   } else {
     OnTrailingHeadersComplete(fin, frame_len, header_list);
   }
-  return !reading_stopped();
 }
 
 void QuicSpdyStream::OnHeadersTooLarge() {
@@ -846,12 +845,10 @@
   const QuicByteCount frame_length = headers_decompressed_
                                          ? trailers_length_.payload_length
                                          : headers_length_.payload_length;
-  bool result = OnStreamHeaderList(
-      /* fin = */ false, frame_length,
-      qpack_decoded_headers_accumulator_->quic_header_list());
-
+  OnStreamHeaderList(/* fin = */ false, frame_length,
+                     qpack_decoded_headers_accumulator_->quic_header_list());
   qpack_decoded_headers_accumulator_.reset();
-  return result;
+  return !sequencer()->IsClosed() && !reading_stopped();
 }
 
 size_t QuicSpdyStream::WriteHeadersImpl(