Let QUIC streams write 16k before ceding. Behind FLAG_quic_batch_writes.

net/quic/quic_session.cc

Index: net/quic/quic_session.cc
diff --git a/net/quic/quic_session.cc b/net/quic/quic_session.cc
index 0eba20fe96901177675db3c9ff84d4d7f0741430..3505f44e57bc0154346b204de4c4e6d72615f849 100644
--- a/net/quic/quic_session.cc
+++ b/net/quic/quic_session.cc
@@ -263,7 +263,7 @@ void QuicSession::OnCanWrite() {
     }
     ReliableQuicStream* stream = GetStream(stream_id);
     if (stream != nullptr && !stream->flow_controller()->IsBlocked()) {
-      // If the stream can't write all bytes, it'll re-add itself to the blocked
+      // If the stream can't write all bytes it'll re-add itself to the blocked
       // list.
       stream->OnCanWrite();
     }
@@ -295,8 +295,11 @@ QuicConsumedData QuicSession::WritevData(
     bool fin,
     FecProtection fec_protection,
     QuicAckListenerInterface* ack_notifier_delegate) {
-  return connection_->SendStreamData(id, iov, offset, fin, fec_protection,
-                                     ack_notifier_delegate);
+  QuicConsumedData data =
+      connection_->SendStreamData(id, iov, offset, fin, fec_protection,
+                                  ack_notifier_delegate);
+  write_blocked_streams_.UpdateBytesForStream(id, data.bytes_consumed);
+  return data;
 }
 
 void QuicSession::SendRstStream(QuicStreamId id,
@@ -752,7 +755,7 @@ void QuicSession::MarkConnectionLevelWriteBlocked(QuicStreamId id,
     // kHighestPriority.
     priority = kHighestPriority;
   }
-  write_blocked_streams_.PushBack(id, priority);
+  write_blocked_streams_.AddStream(id, priority);
 }
 
 bool QuicSession::HasDataToWrite() const {