Webcrypto: add layout tests for HKDF algorithm

LayoutTests/crypto/subtle/hkdf-unwrapKey-expected.txt

Index: LayoutTests/crypto/subtle/hkdf-unwrapKey-expected.txt
diff --git a/LayoutTests/crypto/subtle/hkdf-unwrapKey-expected.txt b/LayoutTests/crypto/subtle/hkdf-unwrapKey-expected.txt
new file mode 100644
index 0000000000000000000000000000000000000000..8abfca096bcbc934660c87b727477628a6475074
--- /dev/null
+++ b/LayoutTests/crypto/subtle/hkdf-unwrapKey-expected.txt
@@ -0,0 +1,20 @@
+Test unwrapping an HKDF key
+
+On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
+
+
+PASS wrappingKey.algorithm.name is "AES-GCM"
+PASS typeof wrappingKey.extractable is 'boolean'
+PASS wrappingKey.extractable is false
+PASS wrappingKey.usages.join(',') is "encrypt,unwrapKey"
+PASS unwrappedHkdfKey.algorithm.name is "HKDF"
+PASS typeof unwrappedHkdfKey.extractable is 'boolean'
+PASS unwrappedHkdfKey.extractable is false
+PASS unwrappedHkdfKey.usages.join(',') is "deriveBits"
+
+Unwrapping an HKDF key from a format other than raw should fail.

[eroman, 2015/01/12 22:35:23]

Please describe the action being done, not the expected result.
(The expectation reads on its own in this -expected.txt file.)

[nharper, 2015/01/13 00:11:16]

Done.

+error is: NotSupportedError: Unsupported import key format for algorithm
+PASS successfullyParsed is true
+
+TEST COMPLETE
+