diff -up chromium-76.0.3809.100/net/quic/platform/impl/quic_default_proof_providers_impl.cc.vtable-symbol-undefined chromium-76.0.3809.100/net/quic/platform/impl/quic_default_proof_providers_impl.cc
--- chromium-76.0.3809.100/net/quic/platform/impl/quic_default_proof_providers_impl.cc.vtable-symbol-undefined	2019-08-20 21:21:24.901899270 +0200
+++ chromium-76.0.3809.100/net/quic/platform/impl/quic_default_proof_providers_impl.cc	2019-08-20 21:19:30.361746211 +0200
@@ -18,6 +18,7 @@
 #include "net/quic/crypto/proof_verifier_chromium.h"
 #include "net/third_party/quiche/src/quic/platform/api/quic_flags.h"
 #include "net/third_party/quiche/src/quic/platform/api/quic_ptr_util.h"
+#include "net/quic/platform/impl/quic_flags_impl.cc"
 
 DEFINE_QUIC_COMMAND_LINE_FLAG(std::string,
                               certificate_file,