Move IActivationFactoryMethods.ActivateInstance into WinRT.Runtime (#1489)

* Move IActivationFactoryMethods to WinRT.Runtime

* Update projections writer

Author: Sergio0694

src/WinRT.Runtime/Interop/IActivationFactory.cs

@@ -2,9 +2,11 @@
 // Licensed under the MIT License.
 
 using System;
+using System.ComponentModel;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 using WinRT;
+using WinRT.Interop;
 
 namespace WinRT.Interop
 {
@@ -38,6 +40,35 @@ static class IActivationFactoryMethods
 #endif
 
         public static IntPtr AbiToProjectionVftablePtr => IActivationFactory.Vftbl.AbiToProjectionVftablePtr;
+
+        /// <summary>
+        /// Activates an instance from a given activation factory <see cref="IObjectReference"/> instance.
+        /// </summary>
+        /// <param name="objectReference">The input activation factory <see cref="IObjectReference"/> instance to use.</param>
+        /// <returns>The resulting <see cref="IObjectReference"/> instance created from <paramref name="objectReference"/>.</returns>
+        /// <remarks>
+        /// <para>This method assumes <paramref name="objectReference"/> is wrapping an <c>IActivationFactory</c> instance (with no validation).</para>
+        /// <para>This method is only meant to be used by the generated projections, and not by consumers of CsWinRT directly.</para>
+        /// </remarks>
+        [EditorBrowsable(EditorBrowsableState.Never)]
+        public static unsafe IObjectReference ActivateInstanceUnsafe(IObjectReference objectReference)
+        {
+            IntPtr thisPtr = objectReference.ThisPtr;
+            IntPtr instancePtr;
+
+            ExceptionHelpers.ThrowExceptionForHR((*(delegate* unmanaged[Stdcall]<IntPtr, IntPtr*, int>**)thisPtr)[6](thisPtr, &instancePtr));
+
+            GC.KeepAlive(objectReference);
+
+            try
+            {
+                return ComWrappersSupport.GetObjectReferenceForInterface<IUnknownVftbl>(instancePtr);
+            }
+            finally
+            {
+                MarshalInspectable<object>.DisposeAbi(instancePtr);
+            }
+        }
     }
 
     [global::WinRT.ObjectReferenceWrapper(nameof(_obj))]

src/cswinrt/code_writers.h

@@ -2138,7 +2138,7 @@ ComWrappersSupport.RegisterObjectForInterface(this, ThisPtr);
             auto objrefname = w.write_temp("%", bind<write_objref_type_name>(class_type));
 
             w.write(R"(
-public %() : this(%(WinRT.IActivationFactoryMethods.ActivateInstance<IUnknownVftbl>(%)))
+public %() : this(%(global::ABI.WinRT.Interop.IActivationFactoryMethods.ActivateInstanceUnsafe(%)))
 {
 ComWrappersSupport.RegisterObjectForInterface(this, ThisPtr);
 %

src/cswinrt/strings/WinRT.cs

@@ -19,23 +19,6 @@
 
 namespace WinRT
 {
-    internal static class IActivationFactoryMethods
-    {
-        public static unsafe ObjectReference<I> ActivateInstance<I>(IObjectReference obj)
-        {
-            IntPtr instancePtr;
-            global::WinRT.ExceptionHelpers.ThrowExceptionForHR((*(delegate* unmanaged[Stdcall]<IntPtr, IntPtr*, int>**)obj.ThisPtr)[6](obj.ThisPtr, &instancePtr));
-            try
-            {
-                return ComWrappersSupport.GetObjectReferenceForInterface<I>(instancePtr);
-            }
-            finally
-            {
-                MarshalInspectable<object>.DisposeAbi(instancePtr);
-            }
-        }
-    }
-
     internal class ComponentActivationFactory : global::WinRT.Interop.IActivationFactory
     {
         public IntPtr ActivateInstance()