Check that usage isn't empty when generateKey() is called

content/child/webcrypto/test/aes_gcm_unittest.cc

Index: content/child/webcrypto/test/aes_gcm_unittest.cc
diff --git a/content/child/webcrypto/test/aes_gcm_unittest.cc b/content/child/webcrypto/test/aes_gcm_unittest.cc
index 03464145f88948b2b593812faf88486eebcdaada..c5e2a3207c0e0dd43d8ec9b4e2ba335dd1e4c64a 100644
--- a/content/child/webcrypto/test/aes_gcm_unittest.cc
+++ b/content/child/webcrypto/test/aes_gcm_unittest.cc
@@ -114,10 +114,22 @@ TEST(WebCryptoAesGcmTest, GenerateKeyBadLength) {
     SCOPED_TRACE(i);
     EXPECT_EQ(Status::ErrorGenerateKeyLength(),
               GenerateSecretKey(
-                  CreateAesGcmKeyGenAlgorithm(kKeyLen[i]), true, 0, &key));
+                  CreateAesGcmKeyGenAlgorithm(kKeyLen[i]), true,
+                  blink::WebCryptoKeyUsageDecrypt, &key));
   }
 }
 
+TEST(WebCryptoAesGcmTest, GenerateKeyEmptyUsage) {
+  if (!SupportsAesGcm()) {
+    LOG(WARNING) << "AES GCM not supported, skipping tests";
+    return;
+  }
+
+  blink::WebCryptoKey key;
+  EXPECT_EQ(Status::ErrorCreateKeyBadUsages(),
+            GenerateSecretKey(CreateAesGcmKeyGenAlgorithm(256), true, 0, &key));
+}
+
 TEST(WebCryptoAesGcmTest, ImportExportJwk) {
   // Some Linux test runners may not have a new enough version of NSS.
   if (!SupportsAesGcm()) {