Added public api changes for TagHelper project system

src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/ProjectChangeKind.cs

@@ -8,5 +8,6 @@ namespace Microsoft.CodeAnalysis.Razor.ProjectSystem
         Added,
         Removed,
         Changed,
+        TagHelpersChanged,
     }
 }

src/Microsoft.VisualStudio.Editor.Razor/ContextChangeEventArgs.cs

@@ -0,0 +1,17 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+
+namespace Microsoft.VisualStudio.Editor.Razor
+{
+    public sealed class ContextChangeEventArgs : EventArgs
+    {
+        public ContextChangeEventArgs(ContextChangeKind kind)
+        {
+            Kind = kind;
+        }
+
+        public ContextChangeKind Kind { get; }
+    }
+}

src/Microsoft.VisualStudio.Editor.Razor/ContextChangeKind.cs

@@ -0,0 +1,12 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+namespace Microsoft.VisualStudio.Editor.Razor
+{
+    public enum ContextChangeKind
+    {
+        ProjectChanged,
+        EditorSettingsChanged,
+        TagHelpersChanged,
+    }
+}

src/Microsoft.VisualStudio.Editor.Razor/DefaultVisualStudioRazorParser.cs

@@ -3,7 +3,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Diagnostics;
 using System.IO;
 using System.Threading;
 using System.Threading.Tasks;
@@ -133,7 +132,7 @@ namespace Microsoft.VisualStudio.Editor.Razor
         }
 
         // Internal for testing
-        internal void DocumentTracker_ContextChanged(object sender, EventArgs args)
+        internal void DocumentTracker_ContextChanged(object sender, ContextChangeEventArgs args)
         {
             _dispatcher.AssertForegroundThread();
 

src/Microsoft.VisualStudio.Editor.Razor/VisualStudioDocumentTracker.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.Collections.Generic;
+using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.Razor.Editor;
 using Microsoft.CodeAnalysis.Razor.ProjectSystem;
@@ -13,12 +14,14 @@ namespace Microsoft.VisualStudio.Editor.Razor
 {
     public abstract class VisualStudioDocumentTracker
     {
-        public abstract event EventHandler ContextChanged;
+        public abstract event EventHandler<ContextChangeEventArgs> ContextChanged;
 
         internal abstract ProjectExtensibilityConfiguration Configuration { get; }
 
         public abstract EditorSettings EditorSettings { get; }
 
+        public abstract IReadOnlyList<TagHelperDescriptor> TagHelpers { get; }
+
         public abstract bool IsSupportedProject { get; }
 
         public abstract string FilePath { get; }

src/Microsoft.VisualStudio.LanguageServices.Razor/Editor/DefaultVisualStudioDocumentTracker.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.Collections.Generic;
+using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.Razor;
 using Microsoft.CodeAnalysis.Razor.Editor;
@@ -27,7 +28,7 @@ namespace Microsoft.VisualStudio.LanguageServices.Razor.Editor
         private ProjectSnapshot _project;
         private string _projectPath;
 
-        public override event EventHandler ContextChanged;
+        public override event EventHandler<ContextChangeEventArgs> ContextChanged;
 
         public DefaultVisualStudioDocumentTracker(
             string filePath,
@@ -81,6 +82,8 @@ namespace Microsoft.VisualStudio.LanguageServices.Razor.Editor
 
         public override EditorSettings EditorSettings => _editorSettingsManager.Current;
 
+        public override IReadOnlyList<TagHelperDescriptor> TagHelpers => Array.Empty<TagHelperDescriptor>();
+
         public override bool IsSupportedProject => _isSupportedProject;
 
         public override Project Project => _workspace.CurrentSolution.GetProject(_project.UnderlyingProject.Id);
@@ -176,7 +179,7 @@ namespace Microsoft.VisualStudio.LanguageServices.Razor.Editor
             _projectManager.Changed += ProjectManager_Changed;
             _editorSettingsManager.Changed += EditorSettingsManager_Changed;
 
-            OnContextChanged(_project);
+            OnContextChanged(_project, ContextChangeKind.ProjectChanged);
         }
 
         private void Unsubscribe()
@@ -187,17 +190,17 @@ namespace Microsoft.VisualStudio.LanguageServices.Razor.Editor
             // Detached from project.
             _isSupportedProject = false;
             _project = null;
-            OnContextChanged(project: null);
+            OnContextChanged(project: null, kind: ContextChangeKind.ProjectChanged);
         }
 
-        private void OnContextChanged(ProjectSnapshot project)
+        private void OnContextChanged(ProjectSnapshot project, ContextChangeKind kind)
         {
             _project = project;
 
             var handler = ContextChanged;
             if (handler != null)
             {
-                handler(this, EventArgs.Empty);
+                handler(this, new ContextChangeEventArgs(kind));
             }
         }
 
@@ -206,14 +209,21 @@ namespace Microsoft.VisualStudio.LanguageServices.Razor.Editor
             if (_projectPath != null &&
                 string.Equals(_projectPath, e.Project.UnderlyingProject.FilePath, StringComparison.OrdinalIgnoreCase))
             {
-                OnContextChanged(e.Project);
+                if (e.Kind == ProjectChangeKind.TagHelpersChanged)
+                {
+                    OnContextChanged(e.Project, ContextChangeKind.TagHelpersChanged);
+                }
+                else
+                {
+                    OnContextChanged(e.Project, ContextChangeKind.ProjectChanged);
+                }
             }
         }
 
         // Internal for testing
         internal void EditorSettingsManager_Changed(object sender, EditorSettingsChangedEventArgs args)
         {
-            OnContextChanged(_project);
+            OnContextChanged(_project, ContextChangeKind.EditorSettingsChanged);
         }
     }
 }