-Fixed JsonConvert.PopulateObject error with starting comment

Src/Newtonsoft.Json.Tests/JsonConvertTest.cs

@@ -60,6 +60,64 @@ namespace Newtonsoft.Json.Tests
     [TestFixture]
     public class JsonConvertTest : TestFixtureBase
     {
+        public class PopulateTestObject
+        {
+            public decimal Prop { get; set; }
+        }
+
+        [Test]
+        public void PopulateObjectWithHeaderComment()
+        {
+            string json = @"// file header
+{
+  ""prop"": 1.0
+}";
+
+            PopulateTestObject o = new PopulateTestObject();
+            JsonConvert.PopulateObject(json, o);
+
+            Assert.AreEqual(1m, o.Prop);
+        }
+
+        [Test]
+        public void PopulateObjectWithMultipleHeaderComment()
+        {
+            string json = @"// file header
+// another file header?
+{
+  ""prop"": 1.0
+}";
+
+            PopulateTestObject o = new PopulateTestObject();
+            JsonConvert.PopulateObject(json, o);
+
+            Assert.AreEqual(1m, o.Prop);
+        }
+
+        [Test]
+        public void PopulateObjectWithNoContent()
+        {
+            ExceptionAssert.Throws<JsonSerializationException>(() =>
+            {
+                string json = @"";
+
+                PopulateTestObject o = new PopulateTestObject();
+                JsonConvert.PopulateObject(json, o);
+            }, "No JSON content found. Path '', line 0, position 0.");
+        }
+
+        [Test]
+        public void PopulateObjectWithOnlyComment()
+        {
+            ExceptionAssert.Throws<JsonSerializationException>(() =>
+            {
+                string json = @"// file header";
+
+                PopulateTestObject o = new PopulateTestObject();
+                JsonConvert.PopulateObject(json, o);
+            }, "No JSON content found. Path '', line 1, position 14.");
+        }
+
         [Test]
         public void DefaultSettings()
         {

Src/Newtonsoft.Json/Serialization/JsonSerializerInternalReader.cs

@@ -70,8 +70,13 @@ namespace Newtonsoft.Json.Serialization
 
             JsonContract contract = Serializer._contractResolver.ResolveContract(objectType);
 
-            if (reader.TokenType == JsonToken.None)
-                reader.Read();
+            while (reader.TokenType == JsonToken.None || reader.TokenType == JsonToken.Comment)
+            {
+                if (!reader.Read())
+                {
+                    throw JsonSerializationException.Create(reader, "No JSON content found.");
+                }
+            }
 
             if (reader.TokenType == JsonToken.StartArray)
             {