Adding Content-Type header to POST requests for .NET bindings

Author: jimevans

dotnet/src/webdriver/Remote/HttpCommandExecutor.cs

@@ -39,6 +39,7 @@ public class HttpCommandExecutor : ICommandExecutor
         private const string PngMimeType = "image/png";
         private const string Utf8CharsetType = "utf-8";
         private const string RequestAcceptHeader = JsonMimeType + ", " + PngMimeType;
+        private const string RequestContentTypeHeader = JsonMimeType + "; charset=" + Utf8CharsetType;
         private const string UserAgentHeaderTemplate = "selenium/{0} (.net {1})";
         private Uri remoteServerUri;
         private TimeSpan serverResponseTimeout;
@@ -257,6 +258,10 @@ private async Task<HttpResponseInfo> MakeHttpRequest(HttpRequestInfo requestInfo
 
                 byte[] bytes = Encoding.UTF8.GetBytes(eventArgs.RequestBody);
                 requestMessage.Content = new ByteArrayContent(bytes, 0, bytes.Length);
+
+                MediaTypeHeaderValue contentTypeHeader = new MediaTypeHeaderValue(JsonMimeType);
+                contentTypeHeader.CharSet = Utf8CharsetType;
+                requestMessage.Content.Headers.ContentType = contentTypeHeader;
             }
 
             HttpResponseMessage responseMessage = await this.client.SendAsync(requestMessage);