Implement QUIC key extraction.

net/quic/test_tools/crypto_test_utils.cc

Index: net/quic/test_tools/crypto_test_utils.cc
diff --git a/net/quic/test_tools/crypto_test_utils.cc b/net/quic/test_tools/crypto_test_utils.cc
index ca0681ac5b317f8c055628e79aacc01cdda04a5e..712a4d2cbb1454dd5b5d1ebf574dc0a912397ceb 100644
--- a/net/quic/test_tools/crypto_test_utils.cc
+++ b/net/quic/test_tools/crypto_test_utils.cc
@@ -452,6 +452,26 @@ void CryptoTestUtils::CompareClientAndServerKeys(
   StringPiece server_forward_secure_decrypter_iv =
       server_forward_secure_decrypter->GetNoncePrefix();
 
+  StringPiece client_subkey_secret =
+      client->crypto_negotiated_params().subkey_secret;
+  StringPiece server_subkey_secret =
+      server->crypto_negotiated_params().subkey_secret;
+
+
+  const char kSampleLabel[] = "label";
+  const char kSampleContext[] = "context";
+  const int kSampleOutputLength = 32;

[dmz, 2014/07/30 17:58:26]

Do you want to use size_t here like you suggested for me?

[wtc, 2014/07/30 18:09:35]

Done. Originally I wanted to see if it caused a compiler warning on any
platform. (The answer seems to be No based on the try bot results.)

+  string client_key_extraction;
+  string server_key_extraction;
+  EXPECT_TRUE(client->ExportKeyingMaterial(kSampleLabel,
+                                           kSampleContext,
+                                           kSampleOutputLength,
+                                           &client_key_extraction));
+  EXPECT_TRUE(server->ExportKeyingMaterial(kSampleLabel,
+                                           kSampleContext,
+                                           kSampleOutputLength,
+                                           &server_key_extraction));
+
   CompareCharArraysWithHexError("client write key",
                                 client_encrypter_key.data(),
                                 client_encrypter_key.length(),
@@ -492,6 +512,16 @@ void CryptoTestUtils::CompareClientAndServerKeys(
                                 server_forward_secure_encrypter_iv.length(),
                                 client_forward_secure_decrypter_iv.data(),
                                 client_forward_secure_decrypter_iv.length());
+  CompareCharArraysWithHexError("subkey secret",
+                                client_subkey_secret.data(),
+                                client_subkey_secret.length(),
+                                server_subkey_secret.data(),
+                                server_subkey_secret.length());
+  CompareCharArraysWithHexError("sample key extraction",
+                                client_key_extraction.data(),
+                                client_key_extraction.length(),
+                                server_key_extraction.data(),
+                                server_key_extraction.length());
 }
 
 // static