Remove HostHtmlDocumentServiceProvider as it is always NULL

Author: h3xds1nz

src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Interop/BrowserInteropHelper.cs

@@ -87,32 +87,7 @@ internal static bool IsInitialViewerNavigation
             }
         }
 
-        /// <summary>
-        /// Retrieves the IServiceProvider object for the browser we're hosted in.
-        /// This is used for IDispatchEx operations in the script interop feature.
-        /// Critical: Returns critical type UnsafeNativeMethods.IServiceProvider
-        /// </summary>
-        internal static UnsafeNativeMethods.IServiceProvider HostHtmlDocumentServiceProvider
-        {
-            get
-            {
-                // HostHtmlDocumentServiceProvider is used by DynamicScriptObject for IDispatchEx
-                // operations in case of IE. During initialization we get the document node from
-                // the DOM to obtain the required service provider. During this short timeframe
-                // it's valid to have a null-value returned here. In all other cases, we make sure
-                // not to run with a null service provider for sake of security.
-                // See InitializeHostHtmlDocumentServiceProvider as well.
-                /* TODO: straighten this with browser flags to check only when hosted in IE */
-                Invariant.Assert(!(_initializedHostScript && _hostHtmlDocumentServiceProvider == null));
-
-                return _hostHtmlDocumentServiceProvider;
-            }
-        }
-
         private static bool _isInitialViewerNavigation;
-        
-        private static UnsafeNativeMethods.IServiceProvider _hostHtmlDocumentServiceProvider;
-        private static bool _initializedHostScript;
     }
 }
 

src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Interop/DynamicScriptObject.cs

@@ -568,12 +568,12 @@ private HRESULT InvokeOnScriptObject(int dispid, int flags, NativeMethods.DISPPA
             //
             // That is why we switch to invoking the script via IDispatch with SUCS on the methods.
 
-            if (_scriptObjectEx != null)
+            if (_scriptObjectEx != null) // TODO: This code path is never taken outside XBAP
             {
                 // This case takes care of IE hosting where the use of IDispatchEx is recommended by IE people
                 // since the service provider object we can pass here is used by the browser to enforce cross-
                 // zone scripting mitigations. 
-                return _scriptObjectEx.InvokeEx(dispid, Thread.CurrentThread.CurrentCulture.LCID, flags, dp, out result, exInfo, BrowserInteropHelper.HostHtmlDocumentServiceProvider);
+                return _scriptObjectEx.InvokeEx(dispid, Thread.CurrentThread.CurrentCulture.LCID, flags, dp, out result, exInfo, null);
             }
             else
             {