[WebCrypto] Throw syntaxError if keyUsage is empty in ImportKey

content/test/data/webcrypto/ecdh.json

Index: content/test/data/webcrypto/ecdh.json
diff --git a/content/test/data/webcrypto/ecdh.json b/content/test/data/webcrypto/ecdh.json
index d2e2e48c584102327008fcff64271456ba697974..f51f7d103c206af7ffdfc349c005d0d0ec2eb9af 100644
--- a/content/test/data/webcrypto/ecdh.json
+++ b/content/test/data/webcrypto/ecdh.json
@@ -347,28 +347,6 @@
     "error": "OperationError: Length specified for ECDH key derivation is too large. Maximum allowed is 256 bits"
   },
 
-  // The public key parameter is in fact a private key

[eroman, 2014/12/17 21:17:42]

This test should not be removed.

If it is failing with this change, you must instead change the test expectation.

You will probably need to modify the test harness and introduce a
"public_key_error" field.

Search for "private_key_error" to see what I mean.

Once this has been addressed, the rest of the change looks good.

[eroman, 2014/12/17 21:21:03]

Actually I am OK with removing this test, as we have an equivalent one  in:

https://code.google.com/p/chromium/codesearch#chromium/src/third_party/WebKit...

LGTM then

-  // (not allowed by web crypto), even though it could in practice work.
-  {
-    "private_key": {
-      "kty":"EC",
-      "crv":"P-256",
-      "x":"u6dWhaRHrvFF0CiFVuUUFafU6ixveQf9trHDXJ8hgV8",
-      "y":"thSm4LIY35vDD-5LE454eB7TShn919DVVGZ_7tWdjTE",
-      "d":"CQ8uF_-zB1NftLO6ytwKM3Cnuol64PQw5qOuCzQJeFU"
-    },
-    "public_key": {
-      "kty":"EC",
-      "crv":"P-256",
-      "d":"uN2YSQvxuxhQQ9Y1XXjYi1vr2ZTdzuoDX18PYu4LU-0",
-      "x":"S2S3tjygMB0DkM-N9jYUgGLt_9_H6km5P9V6V_KS4_4",
-      "y":"03j8Tyqgrc4R4FAUV2C7-im96yMmfmO_5Om6Kr8YP3o"
-    },
-
-    "length_bits": 256,
-    "error": "InvalidAccess: The public parameter for ECDH key derivation is not a public EC key"
-  },
-
   // Curve mismatch (public key is for P-521 however private key was for P-256).
   {
     "private_key": {