Change CryptoHandshakeMessage::GetTaglist to tag a QuicTagVector*

net/quic/core/crypto/crypto_handshake_message.cc

Index: net/quic/core/crypto/crypto_handshake_message.cc
diff --git a/net/quic/core/crypto/crypto_handshake_message.cc b/net/quic/core/crypto/crypto_handshake_message.cc
index 220c46adfc0d3e2e9551e88adab078dd1afac6d7..0d0813abb843e9570f0ac517458689809a476c47 100644
--- a/net/quic/core/crypto/crypto_handshake_message.cc
+++ b/net/quic/core/crypto/crypto_handshake_message.cc
@@ -79,9 +79,9 @@ void CryptoHandshakeMessage::Erase(QuicTag tag) {
   tag_value_map_.erase(tag);
 }
 
-QuicErrorCode CryptoHandshakeMessage::GetTaglist(QuicTag tag,
-                                                 const QuicTag** out_tags,
-                                                 size_t* out_len) const {
+QuicErrorCode CryptoHandshakeMessage::GetTaglist(
+    QuicTag tag,
+    QuicTagVector* out_tags) const {
   QuicTagValueMap::const_iterator it = tag_value_map_.find(tag);
   QuicErrorCode ret = QUIC_NO_ERROR;
 
@@ -92,13 +92,17 @@ QuicErrorCode CryptoHandshakeMessage::GetTaglist(QuicTag tag,
   }
 
   if (ret != QUIC_NO_ERROR) {
-    *out_tags = nullptr;
-    *out_len = 0;
+    out_tags->clear();
     return ret;
   }
 
-  *out_tags = reinterpret_cast<const QuicTag*>(it->second.data());
-  *out_len = it->second.size() / sizeof(QuicTag);
+  size_t num_tags = it->second.size() / sizeof(QuicTag);
+  out_tags->resize(num_tags);
+  for (size_t i = 0; i < num_tags; ++i) {
+    QuicTag tag;
+    memcpy(&tag, it->second.data() + i * sizeof(tag), sizeof(tag));

[Nico, 2017/06/12 20:32:31]

A few short weeks later, I suddenly remembered this CL and that I forgot to
mention that you could've used
https://cs.chromium.org/chromium/src/base/bit_cast.h?type=cs&q=bit_cast+packa...
here if you can depend on base.

[Ryan Hamilton, 2017/06/12 20:48:41]

Ooo! That's good to know. We can depend on base (though perhaps via a wrapper)
and it looks like we have this function internally too. There are quite a few
places where we do memcpys like this which would also be candidates for
bit_cast.

Thanks!

+    (*out_tags)[i] = tag;
+  }
   return ret;
 }