Remove ForegroundThreadAffinitizedObject usage

src/EditorFeatures/CSharp/EventHookup/EventHookupCommandHandler.cs

@@ -38,8 +38,9 @@ namespace Microsoft.CodeAnalysis.Editor.CSharp.EventHookup
     [ContentType(ContentTypeNames.CSharpContentType)]
     [Name(PredefinedCommandHandlerNames.EventHookup)]
     [Order(Before = PredefinedCommandHandlerNames.AutomaticCompletion)]
-    internal partial class EventHookupCommandHandler : ForegroundThreadAffinitizedObject
+    internal partial class EventHookupCommandHandler
     {
+        private readonly IThreadingContext _threadingContext;
         private readonly IInlineRenameService _inlineRenameService;
         private readonly IAsynchronousOperationListener _asyncListener;
         private readonly IGlobalOptionService _globalOptions;
@@ -57,8 +58,8 @@ public EventHookupCommandHandler(
             EventHookupSessionManager eventHookupSessionManager,
             IGlobalOptionService globalOptions,
             IAsynchronousOperationListenerProvider listenerProvider)
-            : base(threadingContext)
         {
+            _threadingContext = threadingContext;
             _inlineRenameService = inlineRenameService;
             _asyncListener = listenerProvider.GetListener(FeatureAttribute.EventHookup);
             _globalOptions = globalOptions;

src/EditorFeatures/CSharp/EventHookup/EventHookupCommandHandler_SessionCancellingCommands.cs

@@ -6,6 +6,7 @@
 
 using Microsoft.VisualStudio.Commanding;
 using Microsoft.VisualStudio.Text.Editor.Commanding.Commands;
+using Roslyn.Utilities;
 
 namespace Microsoft.CodeAnalysis.Editor.CSharp.EventHookup
 {
@@ -16,14 +17,14 @@ internal partial class EventHookupCommandHandler :
 
         public bool ExecuteCommand(EscapeKeyCommandArgs args, CommandExecutionContext context)
         {
-            AssertIsForeground();
+            Contract.ThrowIfFalse(_threadingContext.HasMainThread);
             EventHookupSessionManager.CancelAndDismissExistingSessions();
             return false;
         }
 
         public CommandState GetCommandState(EscapeKeyCommandArgs args)
         {
-            AssertIsForeground();
+            Contract.ThrowIfFalse(_threadingContext.HasMainThread);
             return CommandState.Unspecified;
         }
     }

src/EditorFeatures/CSharp/EventHookup/EventHookupCommandHandler_TabKeyCommand.cs

@@ -36,7 +36,7 @@ internal partial class EventHookupCommandHandler : IChainedCommandHandler<TabKey
     {
         public void ExecuteCommand(TabKeyCommandArgs args, Action nextHandler, CommandExecutionContext context)
         {
-            AssertIsForeground();
+            Contract.ThrowIfFalse(_threadingContext.HasMainThread);
             if (!_globalOptions.GetOption(InternalFeatureOnOffOptions.EventHookup))
             {
                 nextHandler();
@@ -55,7 +55,7 @@ public void ExecuteCommand(TabKeyCommandArgs args, Action nextHandler, CommandEx
 
         public CommandState GetCommandState(TabKeyCommandArgs args, Func<CommandState> nextHandler)
         {
-            AssertIsForeground();
+            Contract.ThrowIfFalse(_threadingContext.HasMainThread);
             if (EventHookupSessionManager.CurrentSession != null)
             {
                 return CommandState.Available;
@@ -68,7 +68,7 @@ public CommandState GetCommandState(TabKeyCommandArgs args, Func<CommandState> n
 
         private void HandleTabWorker(ITextView textView, ITextBuffer subjectBuffer, Action nextHandler, CancellationToken cancellationToken)
         {
-            AssertIsForeground();
+            Contract.ThrowIfFalse(_threadingContext.HasMainThread);
 
             // For test purposes only!
             if (EventHookupSessionManager.CurrentSession.TESTSessionHookupMutex != null)
@@ -107,7 +107,7 @@ private void HandleTabWorker(ITextView textView, ITextBuffer subjectBuffer, Acti
 
         private void GenerateAndAddEventHandler(ITextView textView, ITextBuffer subjectBuffer, string eventHandlerMethodName, Action nextHandler, CancellationToken cancellationToken)
         {
-            AssertIsForeground();
+            Contract.ThrowIfFalse(_threadingContext.HasMainThread);
 
             using (Logger.LogBlock(FunctionId.EventHookup_Generate_Handler, cancellationToken))
             {
@@ -151,7 +151,7 @@ private Solution CreateSolutionWithEventHandler(
             out int plusEqualTokenEndPosition,
             CancellationToken cancellationToken)
         {
-            AssertIsForeground();
+            Contract.ThrowIfFalse(_threadingContext.HasMainThread);
 
             // Mark the += token with an annotation so we can find it after formatting
             var plusEqualsTokenAnnotation = new SyntaxAnnotation();
@@ -289,7 +289,7 @@ private static IMethodSymbol GetMethodSymbol(
 
         private void BeginInlineRename(ITextView textView, int plusEqualTokenEndPosition, CancellationToken cancellationToken)
         {
-            AssertIsForeground();
+            Contract.ThrowIfFalse(_threadingContext.HasMainThread);
 
             if (_inlineRenameService.ActiveSession == null)
             {

src/EditorFeatures/CSharp/EventHookup/EventHookupCommandHandler_TypeCharCommand.cs

@@ -13,14 +13,15 @@
 using Microsoft.VisualStudio.Text;
 using Microsoft.VisualStudio.Text.Editor;
 using Microsoft.VisualStudio.Text.Editor.Commanding.Commands;
+using Roslyn.Utilities;
 
 namespace Microsoft.CodeAnalysis.Editor.CSharp.EventHookup
 {
     internal partial class EventHookupCommandHandler : IChainedCommandHandler<TypeCharCommandArgs>
     {
         public void ExecuteCommand(TypeCharCommandArgs args, Action nextHandler, CommandExecutionContext context)
         {
-            AssertIsForeground();
+            Contract.ThrowIfFalse(_threadingContext.HasMainThread);
             nextHandler();
 
             if (!_globalOptions.GetOption(InternalFeatureOnOffOptions.EventHookup))
@@ -58,7 +59,7 @@ public void ExecuteCommand(TypeCharCommandArgs args, Action nextHandler, Command
 
         private bool IsTextualPlusEquals(ITextView textView, ITextBuffer subjectBuffer)
         {
-            AssertIsForeground();
+            Contract.ThrowIfFalse(_threadingContext.HasMainThread);
 
             var caretPoint = textView.GetCaretPoint(subjectBuffer);
             if (!caretPoint.HasValue)
@@ -72,7 +73,7 @@ private bool IsTextualPlusEquals(ITextView textView, ITextBuffer subjectBuffer)
 
         public CommandState GetCommandState(TypeCharCommandArgs args, Func<CommandState> nextHandler)
         {
-            AssertIsForeground();
+            Contract.ThrowIfFalse(_threadingContext.HasMainThread);
             return nextHandler();
         }
     }

src/EditorFeatures/CSharp/EventHookup/EventHookupSessionManager.cs

@@ -16,12 +16,15 @@
 using Microsoft.VisualStudio.Text;
 using Microsoft.VisualStudio.Text.Adornments;
 using Microsoft.VisualStudio.Text.Editor;
+using Roslyn.Utilities;
 
 namespace Microsoft.CodeAnalysis.Editor.CSharp.EventHookup
 {
     [Export]
-    internal sealed partial class EventHookupSessionManager : ForegroundThreadAffinitizedObject
+    internal sealed partial class EventHookupSessionManager
     {
+        public readonly IThreadingContext ThreadingContext;
+
         private readonly IToolTipService _toolTipService;
         private IToolTipPresenter _toolTipPresenter;
 
@@ -33,14 +36,14 @@ internal sealed partial class EventHookupSessionManager : ForegroundThreadAffini
         [ImportingConstructor]
         [Obsolete(MefConstruction.ImportingConstructorMessage, error: true)]
         public EventHookupSessionManager(IThreadingContext threadingContext, IToolTipService toolTipService)
-            : base(threadingContext)
         {
+            ThreadingContext = threadingContext;
             _toolTipService = toolTipService;
         }
 
         internal void EventHookupFoundInSession(EventHookupSession analyzedSession)
         {
-            AssertIsForeground();
+            Contract.ThrowIfFalse(ThreadingContext.HasMainThread);
 
             var caretPoint = analyzedSession.TextView.GetCaretPoint(analyzedSession.SubjectBuffer);
 
@@ -114,7 +117,7 @@ internal void BeginSession(
 
         internal void CancelAndDismissExistingSessions()
         {
-            AssertIsForeground();
+            Contract.ThrowIfFalse(ThreadingContext.HasMainThread);
 
             if (CurrentSession != null)
             {
@@ -137,7 +140,7 @@ internal void CancelAndDismissExistingSessions()
         /// </summary>
         private void TextBuffer_Changed(object sender, TextContentChangedEventArgs e)
         {
-            AssertIsForeground();
+            Contract.ThrowIfFalse(ThreadingContext.HasMainThread);
 
             foreach (var change in e.Changes)
             {
@@ -154,7 +157,7 @@ private void TextBuffer_Changed(object sender, TextContentChangedEventArgs e)
         /// </summary>
         private void Caret_PositionChanged(object sender, EventArgs e)
         {
-            AssertIsForeground();
+            Contract.ThrowIfFalse(ThreadingContext.HasMainThread);
 
             if (CurrentSession == null)
             {

src/EditorFeatures/CSharp/EventHookup/EventHookupSessionManager_EventHookupSession.cs

@@ -37,9 +37,10 @@ internal sealed partial class EventHookupSessionManager
         /// += is being used to add an event handler to an event. If it is, then we also determine 
         /// a candidate name for the event handler.
         /// </summary>
-        internal class EventHookupSession : ForegroundThreadAffinitizedObject
+        internal class EventHookupSession
         {
             public readonly Task<string> GetEventNameTask;
+            private readonly IThreadingContext _threadingContext;
             private readonly CancellationTokenSource _cancellationTokenSource;
             private readonly ITrackingPoint _trackingPoint;
             private readonly ITrackingSpan _trackingSpan;
@@ -55,7 +56,7 @@ public ITrackingPoint TrackingPoint
             {
                 get
                 {
-                    AssertIsForeground();
+                    Contract.ThrowIfFalse(_threadingContext.HasMainThread);
                     return _trackingPoint;
                 }
             }
@@ -64,7 +65,7 @@ public ITrackingSpan TrackingSpan
             {
                 get
                 {
-                    AssertIsForeground();
+                    Contract.ThrowIfFalse(_threadingContext.HasMainThread);
                     return _trackingSpan;
                 }
             }
@@ -73,7 +74,7 @@ public ITextView TextView
             {
                 get
                 {
-                    AssertIsForeground();
+                    Contract.ThrowIfFalse(_threadingContext.HasMainThread);
                     return _textView;
                 }
             }
@@ -82,14 +83,14 @@ public ITextBuffer SubjectBuffer
             {
                 get
                 {
-                    AssertIsForeground();
+                    Contract.ThrowIfFalse(_threadingContext.HasMainThread);
                     return _subjectBuffer;
                 }
             }
 
             public void Cancel()
             {
-                AssertIsForeground();
+                Contract.ThrowIfFalse(_threadingContext.HasMainThread);
                 _cancellationTokenSource.Cancel();
             }
 
@@ -100,9 +101,8 @@ public EventHookupSession(
                 ITextBuffer subjectBuffer,
                 IAsynchronousOperationListener asyncListener,
                 Mutex testSessionHookupMutex)
-                : base(eventHookupSessionManager.ThreadingContext)
             {
-                AssertIsForeground();
+                _threadingContext = eventHookupSessionManager.ThreadingContext;
                 _cancellationTokenSource = new CancellationTokenSource();
                 var cancellationToken = _cancellationTokenSource.Token;
                 _textView = textView;
@@ -129,7 +129,7 @@ public EventHookupSession(
                     var continuedTask = this.GetEventNameTask.SafeContinueWithFromAsync(
                         async t =>
                         {
-                            await ThreadingContext.JoinableTaskFactory.SwitchToMainThreadAsync(alwaysYield: true, cancellationToken);
+                            await _threadingContext.JoinableTaskFactory.SwitchToMainThreadAsync(alwaysYield: true, cancellationToken);
 
                             if (t.Result != null)
                             {
@@ -153,7 +153,7 @@ public EventHookupSession(
 
             private async Task<string> DetermineIfEventHookupAndGetHandlerNameAsync(Document document, int position, CancellationToken cancellationToken)
             {
-                AssertIsBackground();
+                Contract.ThrowIfTrue(_threadingContext.HasMainThread);
 
                 // For test purposes only!
                 if (TESTSessionHookupMutex != null)
@@ -191,7 +191,7 @@ private async Task<string> DetermineIfEventHookupAndGetHandlerNameAsync(Document
 
             private async Task<SyntaxToken?> GetPlusEqualsTokenInsideAddAssignExpressionAsync(Document document, int position, CancellationToken cancellationToken)
             {
-                AssertIsBackground();
+                Contract.ThrowIfTrue(_threadingContext.HasMainThread);
                 var syntaxTree = await document.GetSyntaxTreeAsync(cancellationToken).ConfigureAwait(false);
                 var token = syntaxTree.FindTokenOnLeftOfPosition(position, cancellationToken);
 
@@ -210,7 +210,7 @@ private async Task<string> DetermineIfEventHookupAndGetHandlerNameAsync(Document
 
             private IEventSymbol GetEventSymbol(SemanticModel semanticModel, SyntaxToken plusEqualsToken, CancellationToken cancellationToken)
             {
-                AssertIsBackground();
+                Contract.ThrowIfTrue(_threadingContext.HasMainThread);
                 if (plusEqualsToken.Parent is not AssignmentExpressionSyntax parentToken)
                 {
                     return null;
@@ -229,7 +229,7 @@ private string GetEventHandlerName(
                 IEventSymbol eventSymbol, SyntaxToken plusEqualsToken, SemanticModel semanticModel,
                 ISyntaxFactsService syntaxFactsService, NamingRule namingRule)
             {
-                AssertIsBackground();
+                Contract.ThrowIfTrue(_threadingContext.HasMainThread);
                 var objectPart = GetNameObjectPart(eventSymbol, plusEqualsToken, semanticModel, syntaxFactsService);
                 var basename = namingRule.NamingStyle.CreateName(ImmutableArray.Create(
                     string.Format("{0}_{1}", objectPart, eventSymbol.Name)));
@@ -249,7 +249,7 @@ private string GetEventHandlerName(
             /// </summary>
             private string GetNameObjectPart(IEventSymbol eventSymbol, SyntaxToken plusEqualsToken, SemanticModel semanticModel, ISyntaxFactsService syntaxFactsService)
             {
-                AssertIsBackground();
+                Contract.ThrowIfTrue(_threadingContext.HasMainThread);
                 var parentToken = plusEqualsToken.Parent as AssignmentExpressionSyntax;
 
                 if (parentToken.Left is MemberAccessExpressionSyntax memberAccessExpression)

src/EditorFeatures/Core/Classification/Semantic/AbstractSemanticOrEmbeddedClassificationViewTaggerProvider.cs

@@ -58,7 +58,7 @@ protected AbstractSemanticOrEmbeddedClassificationViewTaggerProvider(
 
         protected sealed override ITaggerEventSource CreateEventSource(ITextView? textView, ITextBuffer subjectBuffer)
         {
-            AssertIsForeground();
+            Contract.ThrowIfFalse(this.ThreadingContext.HasMainThread);
             Contract.ThrowIfNull(textView);
 
             // Note: we don't listen for OnTextChanged.  They'll get reported by the ViewSpan changing and also the
@@ -78,7 +78,7 @@ protected sealed override ITaggerEventSource CreateEventSource(ITextView? textVi
 
         protected sealed override IEnumerable<SnapshotSpan> GetSpansToTag(ITextView? textView, ITextBuffer subjectBuffer)
         {
-            AssertIsForeground();
+            Contract.ThrowIfFalse(this.ThreadingContext.HasMainThread);
             Contract.ThrowIfNull(textView);
 
             // Find the visible span some 100 lines +/- what's actually in view.  This way

src/EditorFeatures/Core/EditAndContinue/ActiveStatementTaggerProvider.cs

@@ -53,7 +53,7 @@ public ActiveStatementTaggerProvider(
 
         protected override ITaggerEventSource CreateEventSource(ITextView? textView, ITextBuffer subjectBuffer)
         {
-            AssertIsForeground();
+            Contract.ThrowIfFalse(this.ThreadingContext.HasMainThread);
 
             return TaggerEventSources.Compose(
                 new EventSource(subjectBuffer),

src/EditorFeatures/Core/InlineHints/InlineHintsDataTaggerProvider.cs

@@ -66,7 +66,7 @@ protected override ITaggerEventSource CreateEventSource(ITextView? textView, ITe
         {
             Contract.ThrowIfNull(textView);
             return TaggerEventSources.Compose(
-                TaggerEventSources.OnViewSpanChanged(ThreadingContext, textView),
+                TaggerEventSources.OnViewSpanChanged(this.ThreadingContext, textView),
                 TaggerEventSources.OnWorkspaceChanged(subjectBuffer, _listener),
                 TaggerEventSources.OnOptionChanged(subjectBuffer, InlineHintsGlobalStateOption.DisplayAllOverride),
                 TaggerEventSources.OnOptionChanged(subjectBuffer, InlineHintsOptionsStorage.EnabledForParameters),
@@ -85,7 +85,7 @@ protected override ITaggerEventSource CreateEventSource(ITextView? textView, ITe
 
         protected override IEnumerable<SnapshotSpan> GetSpansToTag(ITextView? textView, ITextBuffer subjectBuffer)
         {
-            this.AssertIsForeground();
+            Contract.ThrowIfFalse(this.ThreadingContext.HasMainThread);
             Contract.ThrowIfNull(textView);
 
             // Find the visible span some 100 lines +/- what's actually in view.  This way