[webcrypto] Reject AES-GCM tag lengths other than 32, 64, 96, 104, 112, 120, 128.

content/renderer/webcrypto/platform_crypto_nss.cc

Index: content/renderer/webcrypto/platform_crypto_nss.cc
diff --git a/content/renderer/webcrypto/platform_crypto_nss.cc b/content/renderer/webcrypto/platform_crypto_nss.cc
index c297c204c023c2bc3428fe10fcb706ddcc1e95f6..4cc7b3722e9d48f0ac1e8dcf44dd04e044b6f265 100644
--- a/content/renderer/webcrypto/platform_crypto_nss.cc
+++ b/content/renderer/webcrypto/platform_crypto_nss.cc
@@ -293,9 +293,6 @@ Status AesGcmEncryptDecrypt(EncryptOrDecrypt mode,
   if (!g_aes_gcm_support.Get().IsSupported())
     return Status::ErrorUnsupported();
 
-  // TODO(eroman): Is this necessary?
-  if ((tag_length_bits % 8) != 0)
-    return Status::ErrorInvalidAesGcmTagLength();
   unsigned int tag_length_bytes = tag_length_bits / 8;
 
   CK_GCM_PARAMS gcm_params = {0};