Throw a SyntaxError when importing keys with invalid usages

BUG=425651
R=eroman@chromium.org

Review URL: https://codereview.chromium.org/689883002

Cr-Commit-Position: refs/heads/master@{#302696}

content/child/webcrypto/status.cc

@@ -239,7 +239,7 @@ Status Status::ErrorGenerateKeyLength() {
 }
 
 Status Status::ErrorCreateKeyBadUsages() {
-  return Status(blink::WebCryptoErrorTypeData,
+  return Status(blink::WebCryptoErrorTypeSyntax,
                 "Cannot create a key using the specified key usages.");
 }