Annotate IDebugStateChangeListener with UIContext guid. (#41599)

The debugger will use this to delay load Roslyn EnC until its needed.

src/VisualStudio/Core/Def/Guids.cs

@@ -28,10 +28,16 @@ internal static class Guids
         public const string CSharpLibraryIdString = "58F1BAD0-2288-45b9-AC3A-D56398F7781D";
         public const string CSharpReplPackageIdString = "c5edd1ee-c43b-4360-9ce4-6b993ca12897";
 
+        /// <summary>
+        /// <see cref="UIContext"/> that indicates <see cref="VisualStudioWorkspace"/> contains a project that supports Edit and Continue.
+        /// </summary>
+        public const string EncCapableProjectExistsInWorkspaceUIContextString = "0C89AE24-6D19-474C-A3AA-DC3B66FDBB5F";
+
         /// <summary>
         /// A <see cref="UIContext"/> that is set if there is a C# project in the <see cref="VisualStudioWorkspace"/>.
         /// </summary>
-        public static readonly Guid CSharpProjectExistsInWorkspaceUIContext = new Guid("CA719A03-D55C-48F9-85DE-D934346E7F70");
+        public const string CSharpProjectExistsInWorkspaceUIContextString = "CA719A03-D55C-48F9-85DE-D934346E7F70";
+        public static readonly Guid CSharpProjectExistsInWorkspaceUIContext = new Guid(CSharpProjectExistsInWorkspaceUIContextString);
 
         public const string CSharpProjectRootIdString = "C7FEDB89-B36D-4a62-93F4-DC7A95999921";
 
@@ -81,7 +87,8 @@ internal static class Guids
         /// <summary>
         /// A <see cref="UIContext"/> that is set if there is a Visual Basic project in the <see cref="VisualStudioWorkspace"/>.
         /// </summary>
-        public static readonly Guid VisualBasicProjectExistsInWorkspaceUIContext = new Guid("EEC3DF0D-6D3F-4544-ABF9-8E26E6A90275");
+        public const string VisualBasicProjectExistsInWorkspaceUIContextString = "EEC3DF0D-6D3F-4544-ABF9-8E26E6A90275";
+        public static readonly Guid VisualBasicProjectExistsInWorkspaceUIContext = new Guid(VisualBasicProjectExistsInWorkspaceUIContextString);
 
         public static readonly Guid VisualBasicPackageId = new Guid(VisualBasicPackageIdString);
         public static readonly Guid VisualBasicCompilerServiceId = new Guid(VisualBasicCompilerServiceIdString);

src/VisualStudio/Core/Def/Implementation/EditAndContinue/VisualStudioDebugStateChangeListener.cs

@@ -18,6 +18,7 @@
 namespace Microsoft.VisualStudio.LanguageServices.EditAndContinue
 {
     [Export(typeof(IDebugStateChangeListener))]
+    [ExportMetadata("UIContext", Guids.EncCapableProjectExistsInWorkspaceUIContextString)]
     internal sealed class VisualStudioDebugStateChangeListener : IDebugStateChangeListener
     {
         private readonly Workspace _workspace;

src/VisualStudio/Core/Def/RoslynPackage.cs

@@ -42,6 +42,12 @@ namespace Microsoft.VisualStudio.LanguageServices.Setup
     [Guid(Guids.RoslynPackageIdString)]
     [PackageRegistration(UseManagedResourcesOnly = true, AllowsBackgroundLoading = true)]
     [ProvideMenuResource("Menus.ctmenu", version: 17)]
+    [ProvideUIContextRule(
+        Guids.EncCapableProjectExistsInWorkspaceUIContextString,
+        name: "Managed Edit and Continue capability",
+        expression: "CS | VB",
+        termNames: new[] { "CS", "VB" },
+        termValues: new[] { Guids.CSharpProjectExistsInWorkspaceUIContextString, Guids.VisualBasicProjectExistsInWorkspaceUIContextString })]
     internal class RoslynPackage : AbstractPackage
     {
         private VisualStudioWorkspace _workspace;