Account for HTTP/2 padding in receive windows.

net/tools/flip_server/spdy_interface.h

Index: net/tools/flip_server/spdy_interface.h
diff --git a/net/tools/flip_server/spdy_interface.h b/net/tools/flip_server/spdy_interface.h
index 15cf0e945aaf24307976faa1046646d4fa1b2051..20bc0c9ce430d96b66955121590229b48dbc1456 100644
--- a/net/tools/flip_server/spdy_interface.h
+++ b/net/tools/flip_server/spdy_interface.h
@@ -102,6 +102,11 @@ class SpdySM : public BufferedSpdyFramerVisitorInterface, public SMInterface {
                          size_t len,
                          bool fin) override;
 
+  // Called when padding is received (padding length field or padding octets).
+  // |stream_id| The stream receiving data.
+  // |len| The number of padding octets.
+  void OnStreamPadding(SpdyStreamId stream_id, size_t len) override;
+
   // Called when a SETTINGS frame is received.
   // |clear_persisted| True if the respective flag is set on the SETTINGS frame.
   void OnSettings(bool clear_persisted) override {}