Ignore Crypto-Key header values that do not have "dh" values

components/gcm_driver/crypto/gcm_encryption_provider.cc

Index: components/gcm_driver/crypto/gcm_encryption_provider.cc
diff --git a/components/gcm_driver/crypto/gcm_encryption_provider.cc b/components/gcm_driver/crypto/gcm_encryption_provider.cc
index 35015369f5d25a0746e0783489422bf78a21ced6..e9ca7855cdd97525aac91edbd2377e6114e25d21 100644
--- a/components/gcm_driver/crypto/gcm_encryption_provider.cc
+++ b/components/gcm_driver/crypto/gcm_encryption_provider.cc
@@ -150,6 +150,11 @@ void GCMEncryptionProvider::DecryptMessage(
     return;
   }
 
+  // Ignore values that don't include the "dh" property. When using VAPID, it is
+  // valid for the application server to supply multiple values.
+  while (crypto_key_header_iterator.dh().empty() &&

[johnme, 2016/06/30 16:55:58]

The spec requires "at most one entry having a `dh` parameter" but we don't
enforce that. Should we?

[Peter Beverloo, 2016/06/30 18:00:42]

Done.

+         crypto_key_header_iterator.GetNext()) {}
+
   if (crypto_key_header_iterator.dh().empty()) {
     DLOG(ERROR) << "Invalid values supplied in the Crypto-Key header";
     callback.Run(DECRYPTION_RESULT_INVALID_CRYPTO_KEY_HEADER,