[webcrypto] Add key generation for AES-GCM and AES-KW for NSS.

content/renderer/webcrypto/webcrypto_impl_nss.cc

Index: content/renderer/webcrypto/webcrypto_impl_nss.cc
diff --git a/content/renderer/webcrypto/webcrypto_impl_nss.cc b/content/renderer/webcrypto/webcrypto_impl_nss.cc
index cf447adeb2d7b9f830292b9775aab5d531238688..fb9c275b70e650ac1d559583efce3e45420b3712 100644
--- a/content/renderer/webcrypto/webcrypto_impl_nss.cc
+++ b/content/renderer/webcrypto/webcrypto_impl_nss.cc
@@ -185,6 +185,8 @@ CK_MECHANISM_TYPE WebCryptoAlgorithmToGenMechanism(
     const blink::WebCryptoAlgorithm& algorithm) {
   switch (algorithm.id()) {
     case blink::WebCryptoAlgorithmIdAesCbc:
+    case blink::WebCryptoAlgorithmIdAesGcm:
+    case blink::WebCryptoAlgorithmIdAesKw:
       return CKM_AES_KEY_GEN;
     case blink::WebCryptoAlgorithmIdHmac:
       return WebCryptoHashToHMACMechanism(algorithm.hmacKeyParams()->hash());
@@ -644,10 +646,14 @@ bool WebCryptoImpl::GenerateKeyInternal(
   }
 
   switch (algorithm.id()) {
-    case blink::WebCryptoAlgorithmIdAesCbc: {
+    case blink::WebCryptoAlgorithmIdAesCbc:
+    case blink::WebCryptoAlgorithmIdAesGcm:
+    case blink::WebCryptoAlgorithmIdAesKw: {
       const blink::WebCryptoAesKeyGenParams* params =
           algorithm.aesKeyGenParams();
       DCHECK(params);
+      // Ensure the key length is a multiple of 8 bits. Let NSS verify further
+      // algorithm-specific length restrictions.
       if (params->lengthBits() % 8)
         return false;
       keylen_bytes = params->lengthBits() / 8;