[webcrypto] Reject failed operations with a DOMException rather than null.

LayoutTests/crypto/aes-ctr-generateKey-parseAlgorithm-failures.html

Index: LayoutTests/crypto/aes-ctr-generateKey-parseAlgorithm-failures.html
diff --git a/LayoutTests/crypto/aes-ctr-generateKey-parseAlgorithm-failures.html b/LayoutTests/crypto/aes-ctr-generateKey-parseAlgorithm-failures.html
index f0c38f89061c1702003a72a544f1287b2b0fba4c..2d2c24eb377a21544a6526fa7a6a04e58b1a5d5e 100644
--- a/LayoutTests/crypto/aes-ctr-generateKey-parseAlgorithm-failures.html
+++ b/LayoutTests/crypto/aes-ctr-generateKey-parseAlgorithm-failures.html
@@ -18,23 +18,19 @@ keyUsages = ['encrypt', 'decrypt'];
 Promise.resolve(null).then(function() {
     return crypto.subtle.generateKey({ name: 'aes-ctr' }, extractable, keyUsages);
 }).then(failAndFinishJSTest, function(result) {
-    error = result;
-    shouldBeNull("error");
+    logError(result);
 
     return crypto.subtle.generateKey({ name: 'aes-ctr', length: 70000 }, extractable, keyUsages);
 }).then(failAndFinishJSTest, function(result) {
-    error = result;
-    shouldBeNull("error");
+    logError(result);
 
     return crypto.subtle.generateKey({ name: 'aes-ctr', length: -3 }, extractable, keyUsages);
 }).then(failAndFinishJSTest, function(result) {
-    error = result;
-    shouldBeNull("error");
+    logError(result);
 
     return crypto.subtle.generateKey({ name: 'aes-ctr', length: -Infinity }, extractable, keyUsages);
 }).then(failAndFinishJSTest, function(result) {
-    error = result;
-    shouldBeNull("error");
+    logError(result);
 }).then(finishJSTest, failAndFinishJSTest);
 
 </script>