[NOT FOR REVIEW] Ensure contributory behaviour for Web Push encryption.

components/gcm_driver/crypto/p256_key_util_openssl.cc

Index: components/gcm_driver/crypto/p256_key_util_openssl.cc
diff --git a/components/gcm_driver/crypto/p256_key_util_openssl.cc b/components/gcm_driver/crypto/p256_key_util_openssl.cc
index e550b15f3d6e2bebbcdef16eb1fb592da3dda8fe..848e5d3d1caf8f3a385c69300aece7122b7ef2d0 100644
--- a/components/gcm_driver/crypto/p256_key_util_openssl.cc
+++ b/components/gcm_driver/crypto/p256_key_util_openssl.cc
@@ -10,6 +10,8 @@
 #include <openssl/ecdh.h>
 #include <openssl/evp.h>
 
+#include "base/base64url.h"
+
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/strings/string_util.h"
@@ -45,6 +47,16 @@ bool ComputeSharedP256Secret(const base::StringPiece& private_key,
     return false;
   }
 
+  std::vector<uint8_t> pubkey;
+  local_key_pair->ExportPublicKey(&pubkey);
+
+  std::string res(reinterpret_cast<char*>(pubkey.data()), pubkey.size());
+
+  std::string b;
+  base::Base64UrlEncode(res, base::Base64UrlEncodePolicy::OMIT_PADDING, &b);
+
+  LOG(INFO) << "x509 key: [" << b << "]";
+
   crypto::ScopedEC_KEY ec_private_key(
       EVP_PKEY_get1_EC_KEY(local_key_pair->key()));