Fix a bug where QUIC ack frames were not bundled with crypto stream

net/quic/quic_packet_creator.cc

Index: net/quic/quic_packet_creator.cc
diff --git a/net/quic/quic_packet_creator.cc b/net/quic/quic_packet_creator.cc
index 77b39fad766847c0a33ca6de671ee487c1dbaead..4eb0ea99a83774350f3418f176f9e9f72a156443 100644
--- a/net/quic/quic_packet_creator.cc
+++ b/net/quic/quic_packet_creator.cc
@@ -312,6 +312,11 @@ bool QuicPacketCreator::HasPendingFrames() const {
   return !queued_frames_.empty();
 }
 
+bool QuicPacketCreator::HasPendingRetransmittableFrames() const {
+  return queued_retransmittable_frames_.get() != NULL &&
+      !queued_retransmittable_frames_->frames().empty();
+}
+
 size_t QuicPacketCreator::ExpansionOnNewFrame() const {
   // If packet is FEC protected, there's no expansion.
   if (should_fec_protect_) {