Factor out the QUIC socket reading code into a stand alone QuicPacketReader

net/quic/quic_client_session.cc

Index: net/quic/quic_client_session.cc
diff --git a/net/quic/quic_client_session.cc b/net/quic/quic_client_session.cc
index e5fdba734e838e5c9b84f7925176f96a31eca2df..0625f08077d30c5c7c62a77e5668a72b8ee1c2d6 100644
--- a/net/quic/quic_client_session.cc
+++ b/net/quic/quic_client_session.cc
@@ -166,16 +166,14 @@ QuicClientSession::QuicClientSession(
       require_confirmation_(false),
       stream_factory_(stream_factory),
       socket_(socket.Pass()),
-      read_buffer_(new IOBufferWithSize(kMaxPacketSize)),
       transport_security_state_(transport_security_state),
       server_info_(server_info.Pass()),
-      read_pending_(false),
       num_total_streams_(0),
       task_runner_(task_runner),
       net_log_(BoundNetLog::Make(net_log, NetLog::SOURCE_QUIC_SESSION)),
+      packet_reader_(socket_.get(), this, net_log_),
       dns_resolution_end_time_(dns_resolution_end_time),
       logger_(new QuicConnectionLogger(this, connection_description, net_log_)),
-      num_packets_read_(0),
       going_away_(false),
       weak_factory_(this) {
   connection->set_debug_visitor(logger_.get());
@@ -767,32 +765,7 @@ void QuicClientSession::OnProofVerifyDetailsAvailable(
 }
 
 void QuicClientSession::StartReading() {
-  if (read_pending_) {
-    return;
-  }
-  read_pending_ = true;
-  int rv = socket_->Read(read_buffer_.get(),
-                         read_buffer_->size(),
-                         base::Bind(&QuicClientSession::OnReadComplete,
-                                    weak_factory_.GetWeakPtr()));
-  UMA_HISTOGRAM_BOOLEAN("Net.QuicSession.AsyncRead", rv == ERR_IO_PENDING);
-  if (rv == ERR_IO_PENDING) {
-    num_packets_read_ = 0;
-    return;
-  }
-
-  if (++num_packets_read_ > 32) {
-    num_packets_read_ = 0;
-    // Data was read, process it.
-    // Schedule the work through the message loop to 1) prevent infinite
-    // recursion and 2) avoid blocking the thread for too long.
-    base::MessageLoop::current()->PostTask(
-        FROM_HERE,
-        base::Bind(&QuicClientSession::OnReadComplete,
-                   weak_factory_.GetWeakPtr(), rv));
-  } else {
-    OnReadComplete(rv);
-  }
+  packet_reader_.StartReading();
 }
 
 void QuicClientSession::CloseSessionOnError(int error) {
@@ -874,33 +847,23 @@ base::WeakPtr<QuicClientSession> QuicClientSession::GetWeakPtr() {
   return weak_factory_.GetWeakPtr();
 }
 
-void QuicClientSession::OnReadComplete(int result) {
-  read_pending_ = false;
-  if (result == 0)
-    result = ERR_CONNECTION_CLOSED;
-
-  if (result < 0) {
-    DVLOG(1) << "Closing session on read error: " << result;
-    UMA_HISTOGRAM_SPARSE_SLOWLY("Net.QuicSession.ReadError", -result);
-    NotifyFactoryOfSessionGoingAway();
-    CloseSessionOnErrorInner(result, QUIC_PACKET_READ_ERROR);
-    NotifyFactoryOfSessionClosedLater();
-    return;
-  }
+void QuicClientSession::OnReadError(int result) {
+  DVLOG(1) << "Closing session on read error: " << result;
+  UMA_HISTOGRAM_SPARSE_SLOWLY("Net.QuicSession.ReadError", -result);
+  NotifyFactoryOfSessionGoingAway();
+  CloseSessionOnErrorInner(result, QUIC_PACKET_READ_ERROR);
+  NotifyFactoryOfSessionClosedLater();
+}
 
-  QuicEncryptedPacket packet(read_buffer_->data(), result);
-  IPEndPoint local_address;
-  IPEndPoint peer_address;
-  socket_->GetLocalAddress(&local_address);
-  socket_->GetPeerAddress(&peer_address);
-  // ProcessUdpPacket might result in |this| being deleted, so we
-  // use a weak pointer to be safe.
+bool QuicClientSession::OnPacket(const QuicEncryptedPacket& packet,
+                                 IPEndPoint local_address,
+                                 IPEndPoint peer_address) {
   connection()->ProcessUdpPacket(local_address, peer_address, packet);
   if (!connection()->connected()) {
     NotifyFactoryOfSessionClosedLater();
-    return;
+    return false;
   }
-  StartReading();
+  return true;
 }
 
 void QuicClientSession::NotifyFactoryOfSessionGoingAway() {