relnote: Deprecate FLAGS_quic_dont_write_when_flow_unblocked.

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 6085704d964140f5999f04053bb1c99ee7ebba2d..8e3696ba07d6648f3fbbc94d8e5ccb2892576c8d 100644
--- a/net/quic/quic_session.cc
+++ b/net/quic/quic_session.cc
@@ -219,15 +219,7 @@ void QuicSession::OnWindowUpdateFrame(const QuicWindowUpdateFrame& frame) {
     DVLOG(1) << ENDPOINT << "Received connection level flow control window "
                             "update with byte offset: "
              << frame.byte_offset;
-    if (flow_controller_.UpdateSendWindowOffset(frame.byte_offset)) {
-      // Connection level flow control window has increased, so blocked streams
-      // can write again.
-      // TODO(ianswett): I suspect this can be delayed until the packet
-      // processing is complete.
-      if (!FLAGS_quic_dont_write_when_flow_unblocked) {
-        OnCanWrite();
-      }
-    }
+    flow_controller_.UpdateSendWindowOffset(frame.byte_offset);
     return;
   }
   ReliableQuicStream* stream = GetStream(stream_id);