CreateInstance factory overload to pass flag informing wrapper if it should own the native pointer passed to it.

src/Generator/Generators/CLI/CLIHeaders.cs

@@ -380,6 +380,8 @@ namespace CppSharp.Generators.CLI
             WriteLine("static {0}^ {1}(::System::IntPtr native);",
                 @class.Name, Helpers.CreateInstanceIdentifier);
 
+            WriteLine($"static {@class.Name}^ {Helpers.CreateInstanceIdentifier}(::System::IntPtr native, bool {Helpers.OwnsNativeInstanceIdentifier});");
+
             foreach (var ctor in @class.Constructors)
             {
                 if (ASTUtils.CheckIgnoreMethod(ctor) || FunctionIgnored(ctor))

src/Generator/Generators/CLI/CLISources.cs

@@ -670,18 +670,21 @@ namespace CppSharp.Generators.CLI
 
             UnindentAndWriteCloseBrace();
 
-            if (!withOwnNativeInstanceParam)
-            {
-                NewLine();
-                WriteLine("{0}^ {0}::{1}(::System::IntPtr native)", qualifiedIdentifier, Helpers.CreateInstanceIdentifier);
+            string createInstanceParams = withOwnNativeInstanceParam ? $"::System::IntPtr native, bool {Helpers.OwnsNativeInstanceIdentifier}" : "::System::IntPtr native";
+            string createInstanceParamsValues = withOwnNativeInstanceParam ? $"({nativeType}) native.ToPointer(), {Helpers.OwnsNativeInstanceIdentifier}" : $"({nativeType}) native.ToPointer()";
 
-                WriteOpenBraceAndIndent();
+            NewLine();
+            WriteLine($"{qualifiedIdentifier}^ {qualifiedIdentifier}::{Helpers.CreateInstanceIdentifier}({createInstanceParams})");
 
-                WriteLine("return gcnew ::{0}(({1}) native.ToPointer());", qualifiedIdentifier, nativeType);
+            WriteOpenBraceAndIndent();
 
-                UnindentAndWriteCloseBrace();
-                NewLine();
+            WriteLine($"return gcnew ::{qualifiedIdentifier}({createInstanceParamsValues});");
+
+            UnindentAndWriteCloseBrace();
+            NewLine();
 
+            if (!withOwnNativeInstanceParam)
+            {
                 GenerateClassConstructor(@class, true);
             }
         }