Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/System/System.Security.Cryptography.X509Certificates/X509EnhancedKeyUsageExtension.cs

@@ -70,7 +70,10 @@ namespace System.Security.Cryptography.X509Certificates {
 
 			_oid = new Oid (oid, friendlyName);
 			base.Critical = critical;
-			_enhKeyUsage = enhancedKeyUsages.ReadOnlyCopy ();
+			_enhKeyUsage = new OidCollection();
+			foreach (Oid o in enhancedKeyUsages) {
+				_enhKeyUsage.Add(o);
+			}
 			RawData = Encode ();
 		}
 
@@ -81,10 +84,14 @@ namespace System.Security.Cryptography.X509Certificates {
 				switch (_status) {
 				case AsnDecodeStatus.Ok:
 				case AsnDecodeStatus.InformationNotAvailable:
-					if (_enhKeyUsage == null)
-						_enhKeyUsage = new OidCollection ();
-					_enhKeyUsage.ReadOnly = true;
-					return _enhKeyUsage;
+
+					OidCollection oids = new OidCollection();
+					if (_enhKeyUsage != null) {
+						foreach(Oid o in _enhKeyUsage) {
+							oids.Add(o);
+						}
+					}
+					return oids;
 				default:
 					throw new CryptographicException ("Badly encoded extension.");
 				}
@@ -143,8 +150,8 @@ namespace System.Security.Cryptography.X509Certificates {
 		internal byte[] Encode ()
 		{
 			ASN1 ex = new ASN1 (0x30);
-			foreach (Oid oid in _enhKeyUsage) {
-				ex.Add (ASN1Convert.FromOid (oid.Value));
+			foreach (Oid o in _enhKeyUsage) {
+				ex.Add (ASN1Convert.FromOid (o.Value));
 			}
 			return ex.GetBytes ();
 		}