Add JSB support for Methods with optional params

Author: amaitland

CefSharp.Example/BoundObject.cs

@@ -34,6 +34,11 @@ public string Repeat(string str, int n)
             return result;
         }
 
+        public string EchoParamOrDefault(string param = "This is the default value")
+        {
+            return param;
+        }
+
         public void EchoVoid()
         {
         }

CefSharp/Internals/JavascriptMethod.cs

@@ -33,6 +33,11 @@ public class JavascriptMethod
         [DataMember]
         public string JavascriptName { get; set; }
 
+        /// <summary>
+        /// Number of Params this function exepects
+        /// </summary>
+        public int ParameterCount { get; set; }
+
         public override string ToString()
         {
             return ManagedName ?? base.ToString();

CefSharp/Internals/JavascriptObjectRepository.cs

@@ -65,6 +65,20 @@ public bool TryCallMethod(long objectId, string name, object[] parameters, out o
 
             try
             {
+                // Do we have enough arguments? Add Type.Missing for any that we don't have incase of optional params
+                var missingParams = method.ParameterCount - parameters.Length;
+                if (missingParams > 0)
+                {
+                    var paramList = new List<object>(parameters);
+
+                    for (var i = 0; i < missingParams; i++)
+                    {
+                        paramList.Add(Type.Missing);
+                    }
+
+                    parameters = paramList.ToArray();
+                }
+
                 result = method.Function(obj.Value, parameters);
 
                 if(result != null && IsComplexType(result.GetType()))
@@ -216,6 +230,7 @@ private static JavascriptMethod CreateJavaScriptMethod(MethodInfo methodInfo)
             jsMethod.ManagedName = methodInfo.Name;
             jsMethod.JavascriptName = LowercaseFirst(methodInfo.Name);
             jsMethod.Function = methodInfo.Invoke;
+            jsMethod.ParameterCount = methodInfo.GetParameters().Length;
 
             return jsMethod;
         }