Change the wire format of the ack frame to include a compressed version

net/quic/quic_packet_creator.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/quic/quic_packet_creator.h"
 
 #include "base/basictypes.h"
 #include "base/logging.h"
 #include "net/quic/crypto/quic_random.h"
 #include "net/quic/quic_ack_notifier.h"
@@ skipping 361 matching lines @@
       << "Attempt to serialize empty packet";
   DCHECK_GE(sequence_number_ + 1, fec_group_number_);
   QuicPacketHeader header;
   FillPacketHeader(should_fec_protect_ ? fec_group_number_ : 0, false, &header);
 
   MaybeAddPadding();
 
   size_t max_plaintext_size =
       framer_->GetMaxPlaintextSize(max_packet_length_);
   DCHECK_GE(max_plaintext_size, packet_size_);
-  // ACK Frames will be truncated only if they're the only frame in the packet,
-  // and if packet_size_ was set to max_plaintext_size. If truncation occurred,
-  // then GetSerializedFrameLength will have returned all bytes free.
-  bool possibly_truncated = packet_size_ == max_plaintext_size &&
-                            queued_frames_.size() == 1 &&
-                            queued_frames_.back().type == ACK_FRAME;
+  // ACK Frames will be truncated due to length only if they're the only frame
+  // in the packet, and if packet_size_ was set to max_plaintext_size. If
+  // truncation due to length occurred, then GetSerializedFrameLength will have
+  // returned all bytes free.
+  bool possibly_truncated_by_length = packet_size_ == max_plaintext_size &&
+      queued_frames_.size() == 1 &&
+      queued_frames_.back().type == ACK_FRAME;
   SerializedPacket serialized =
       framer_->BuildDataPacket(header, queued_frames_, packet_size_);
   LOG_IF(DFATAL, !serialized.packet)
       << "Failed to serialize " << queued_frames_.size() << " frames.";
   // Because of possible truncation, we can't be confident that our
   // packet size calculation worked correctly.
-  if (!possibly_truncated) {
+  if (!possibly_truncated_by_length) {
     DCHECK_EQ(packet_size_, serialized.packet->length());
   }
   packet_size_ = 0;
   queued_frames_.clear();
   serialized.retransmittable_frames = queued_retransmittable_frames_.release();
   return serialized;
 }
 
 SerializedPacket QuicPacketCreator::SerializeFec() {
   if (fec_group_.get() == NULL || fec_group_->NumReceivedPackets() <= 0) {
@@ skipping 106 matching lines @@
   if (BytesFree() == 0) {
     // Don't pad full packets.
     return;
   }
   QuicPaddingFrame padding;
   bool success = AddFrame(QuicFrame(&padding), false);
   DCHECK(success);
 }
 
 }  // namespace net