Revert "third_party/protobuf: Update to HEAD (83d681ee2c)"

third_party/protobuf/csharp/src/Google.Protobuf.Test/Compatibility/TypeExtensionsTest.cs

 #region Copyright notice and license
 // Protocol Buffers - Google's data interchange format
 // Copyright 2015 Google Inc.  All rights reserved.
 // https://developers.google.com/protocol-buffers/
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
@@ skipping 16 matching lines @@
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #endregion
 using NUnit.Framework;
 using System;
 using System.Collections.Generic;
 using System.Reflection;
 
-#if !DOTNET35
 namespace Google.Protobuf.Compatibility
 {
     public class TypeExtensionsTest
     {
         public class DerivedList : List<string> { }
         public string PublicProperty { get; set; }
         private string PrivateProperty { get; set; }
 
         public void PublicMethod()
         {
         }
 
         private void PrivateMethod()
         {
         }
 
         [Test]
+        [TestCase(typeof(int), true)]
+        [TestCase(typeof(int?), true)]
+        [TestCase(typeof(Nullable<>), true)]
+        [TestCase(typeof(WireFormat.WireType), true)]
+        [TestCase(typeof(string), false)]
+        [TestCase(typeof(object), false)]
+        [TestCase(typeof(Enum), false)]
+        [TestCase(typeof(ValueType), false)]
+        [TestCase(typeof(TypeExtensionsTest), false)]
+        [TestCase(typeof(Action), false)]
+        [TestCase(typeof(Action<>), false)]
+        [TestCase(typeof(IDisposable), false)]
+        public void IsValueType(Type type, bool expected)
+        {
+            Assert.AreEqual(expected, TypeExtensions.IsValueType(type));
+        }
+
+        [Test]
         [TestCase(typeof(object), typeof(string), true)]
         [TestCase(typeof(object), typeof(int), true)]
         [TestCase(typeof(string), typeof(string), true)]
         [TestCase(typeof(string), typeof(object), false)]
         [TestCase(typeof(string), typeof(int), false)]
         [TestCase(typeof(int), typeof(int), true)]
         [TestCase(typeof(ValueType), typeof(int), true)]
         [TestCase(typeof(long), typeof(int), false)] // 
         public void IsAssignableFrom(Type target, Type argument, bool expected)
         {
@@ skipping 42 matching lines @@
         }
 
         [Test]
         [TestCase(typeof(List<string>), "IndexOf")]
         public void GetMethod_Ambiguous(Type type, string name)
         {
             Assert.Throws<AmbiguousMatchException>(() => TypeExtensions.GetMethod(type, name));
         }
     }
 }
-#endif