[src] Remove ObjectWrapper.

ObjectWrapper is not safe, and in any case incompatible with .NET 5.

runtime/COOP.md

@@ -94,14 +94,6 @@ This has the same problem as xamarin_invoke_trampoline,
 having to construct parameters to a managed function
 while at the same time being able to switch to safe mode.
 
-ObjectWrapper
--------------
-
-This is not safe, and must be replaced with safe alternatives:
-
-* icall
-* GCHandle
-
 Debugging tips
 ==============
 

src/ObjCRuntime/ObjectWrapper.cs

@@ -1,30 +0,0 @@
-using System;
-using System.Runtime.InteropServices;
-
-namespace ObjCRuntime {
-	[StructLayout(LayoutKind.Explicit)]
-	internal struct ObjectWrapper {
-		[FieldOffset(0)] object obj;
-		[FieldOffset(0)] IntPtr handle;
-
-		internal static IntPtr Convert (object obj) {
-			if (obj == null)
-				return IntPtr.Zero;
-
-			ObjectWrapper wrapper = new ObjectWrapper ();
-
-			wrapper.obj = obj;
-
-			return wrapper.handle;
-		}
-		
-		internal static object Convert (IntPtr ptr) 
-		{
-			ObjectWrapper wrapper = new ObjectWrapper ();
-			
-			wrapper.handle = ptr;
-				
-			return wrapper.obj;
-		}
-	}
-}

src/frameworks.sources

@@ -1778,7 +1778,6 @@ SHARED_SOURCES = \
 	ObjCRuntime/Method.cs \
 	ObjCRuntime/MethodDescription.cs \
 	ObjCRuntime/NSStringMarshal.cs \
-	ObjCRuntime/ObjectWrapper.cs \
 	ObjCRuntime/Registrar.cs \
 	ObjCRuntime/ReleaseAttribute.cs \
 	ObjCRuntime/RequiredFrameworkAttribute.cs \