Make QuicPacketWriter keep track of socket writability; expose the

net/tools/quic/quic_default_packet_writer.h

Index: net/tools/quic/quic_default_packet_writer.h
diff --git a/net/tools/quic/quic_default_packet_writer.h b/net/tools/quic/quic_default_packet_writer.h
index 20f5fb0db616ed79db3a1edc655277ce55c0656a..75f77571eb56285f1eacd3a5cddb97182b098707 100644
--- a/net/tools/quic/quic_default_packet_writer.h
+++ b/net/tools/quic/quic_default_packet_writer.h
@@ -16,6 +16,10 @@ struct WriteResult;
 
 namespace tools {
 
+namespace test {
+class QuicDispatcherPeer;
+}  // namespace test
+
 // Default packet writer which wraps QuicSocketUtils WritePacket.
 class QuicDefaultPacketWriter : public QuicPacketWriter {
  public:
@@ -29,9 +33,12 @@ class QuicDefaultPacketWriter : public QuicPacketWriter {
       const net::IPEndPoint& peer_address,
       QuicBlockedWriterInterface* blocked_writer) OVERRIDE;
   virtual bool IsWriteBlockedDataBuffered() const OVERRIDE;
+  virtual bool IsWriteBlocked() const OVERRIDE;
+  virtual void SetWritable() OVERRIDE;
 
  private:
   int fd_;
+  bool write_blocked_;
 };
 
 }  // namespace tools