Add support for AB testing in Roslyn.

src/EditorFeatures/Core/Implementation/Suggestions/SuggestedActionsSourceProvider.cs

@@ -30,6 +30,7 @@
 
 namespace Microsoft.CodeAnalysis.Editor.Implementation.Suggestions
 {
+    using Microsoft.CodeAnalysis.Experiments;
     using CodeFixGroupKey = Tuple<DiagnosticData, CodeActionPriority>;
 
     [Export(typeof(ISuggestedActionsSourceProvider))]
@@ -626,10 +627,25 @@ public async Task<bool> HasSuggestedActionsAsync(ISuggestedActionCategorySet req
                 SnapshotSpan range,
                 CancellationToken cancellationToken)
             {
+                if (!requestedActionCategories.Contains(PredefinedSuggestedActionCategoryNames.Refactoring))
+                {
+                    // See if we should still show the light bulb, even if we weren't explicitly 
+                    // asked for refactorings.  We'll show the lightbulb if we're currently
+                    // flighting the "Refactoring" A/B test, or if a special option is set
+                    // enabling this internally.
+
+                    var workspace = document.Project.Solution.Workspace;
+                    var experimentationService = workspace.Services.GetService<IExperimentationService>();
+                    if (!experimentationService.IsExperimentEnabled("Refactoring") &&
+                        !workspace.Options.GetOption(EditorComponentOnOffOptions.ShowCodeRefactoringsWhenQueriedForCodeFixes))
+                    {
+                        return false;
+                    }
+                }
+
                 if (document.Project.Solution.Options.GetOption(EditorComponentOnOffOptions.CodeRefactorings) &&
                     provider._codeRefactoringService != null &&
-                    supportsFeatureService.SupportsRefactorings(document) &&
-                    requestedActionCategories.Contains(PredefinedSuggestedActionCategoryNames.Refactoring))
+                    supportsFeatureService.SupportsRefactorings(document))
                 {
                     TextSpan? selection = null;
                     if (IsForeground())

src/EditorFeatures/Core/Shared/Options/ComponentOnOffOptions.cs

@@ -22,5 +22,10 @@ internal static class EditorComponentOnOffOptions
         [ExportOption]
         public static readonly Option<bool> CodeRefactorings = new Option<bool>(nameof(EditorComponentOnOffOptions), nameof(CodeRefactorings), defaultValue: true,
             storageLocations: new LocalUserProfileStorageLocation(LocalRegistryPath + "Code Refactorings"));
+
+        [ExportOption]
+        public static readonly Option<bool> ShowCodeRefactoringsWhenQueriedForCodeFixes = new Option<bool>(
+            nameof(EditorComponentOnOffOptions), nameof(ShowCodeRefactoringsWhenQueriedForCodeFixes), defaultValue: false,
+            storageLocations: new LocalUserProfileStorageLocation(LocalRegistryPath + nameof(ShowCodeRefactoringsWhenQueriedForCodeFixes)));
     }
-}
+}
\ No newline at end of file

src/VisualStudio/Core/Def/Experimentation/IVsExperimentationService.cs

+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+using System;
+using System.Runtime.InteropServices;
+using Microsoft.VisualStudio.Shell.Interop;
+
+namespace Microsoft.Internal.VisualStudio.Shell.Interop
+{
+    [Guid("6F05B225-83BF-40A3-A32A-47FA8443E868")]
+    [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
+    internal interface IVsFlightEvents
+    {
+        void OnFlightsChanged();
+    }
+
+    [Guid("61A8FB20-45DF-11E5-A151-FEFF819CDC9F")]
+    [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
+    internal interface IVsExperimentationService
+    {
+        [DispId(1610678272)]
+        Array AllEnabledCachedFlights { get; }
+
+        [return: ComAliasName("EnvDTE.ULONG_PTR")]
+        uint AdviseFlightEvents(IVsFlightEvents flightSink);
+        bool IsCachedFlightEnabled([ComAliasName("OLE.LPCOLESTR")] string flightName);
+        IVsTask IsFlightEnabledAsync([ComAliasName("OLE.LPCOLESTR")] string flightName);
+        void Start();
+        void UnadviseFlightEvents([ComAliasName("EnvDTE.ULONG_PTR")] uint cookie);
+    }
+
+    [Guid("DFF66CB5-603C-4716-89BD-24BD0E8C172C")]
+    [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
+    internal interface SVsExperimentationService
+    {
+    }
+}
\ No newline at end of file

src/VisualStudio/Core/Def/Experimentation/VisualStudioExperimentationService.cs

+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+using System.Composition;
+using Microsoft.CodeAnalysis.Experiments;
+using Microsoft.CodeAnalysis.Host.Mef;
+using Microsoft.Internal.VisualStudio.Shell.Interop;
+using Microsoft.VisualStudio.Shell;
+
+namespace Microsoft.VisualStudio.LanguageServices.Experimentation
+{
+    [ExportWorkspaceService(typeof(IExperimentationService), ServiceLayer.Host), Shared]
+    internal class VisualStudioExperimentationService : IExperimentationService
+    {
+        private readonly IVsExperimentationService _experimentationServiceOpt;
+
+        [ImportingConstructor]
+        public VisualStudioExperimentationService(
+            SVsServiceProvider serviceProvider)
+        {
+            try
+            {
+                _experimentationServiceOpt = (IVsExperimentationService)serviceProvider.GetService(typeof(SVsServiceProvider));
+            }
+            catch
+            {
+            }
+        }
+
+        public bool IsExperimentEnabled(string experimentName)
+            => _experimentationServiceOpt?.IsCachedFlightEnabled(experimentName) ?? false;
+    }
+}
\ No newline at end of file

src/VisualStudio/Core/Def/ServicesVisualStudio.csproj

@@ -46,6 +46,8 @@
     <Compile Include="..\..\..\Compilers\Shared\ShadowCopyAnalyzerAssemblyLoader.cs">
       <Link>InternalUtilities\ShadowCopyAnalyzerAssemblyLoader.cs</Link>
     </Compile>
+    <Compile Include="Experimentation\IVsExperimentationService.cs" />
+    <Compile Include="Experimentation\VisualStudioExperimentationService.cs" />
     <Compile Include="Implementation\AnalyzerDependency\AnalyzerDependencyResults.cs" />
     <Compile Include="IAnalyzerNodeSetup.cs" />
     <Compile Include="Implementation\AnalyzerDependency\AnalyzerDependencyChecker.cs" />

src/Workspaces/Core/Portable/Experiments/IExperimentationService.cs

+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+using System.Composition;
+using Microsoft.CodeAnalysis.Host;
+using Microsoft.CodeAnalysis.Host.Mef;
+
+namespace Microsoft.CodeAnalysis.Experiments
+{
+    internal interface IExperimentationService : IWorkspaceService
+    {
+        bool IsExperimentEnabled(string experimentName);
+    }
+
+    [ExportWorkspaceService(typeof(IExperimentationService)), Shared]
+    internal class DefaultExperimentationService : IExperimentationService
+    {
+        public bool IsExperimentEnabled(string experimentName) => false;
+    }
+}
\ No newline at end of file

src/Workspaces/Core/Portable/Workspaces.csproj

@@ -382,6 +382,7 @@
     <Compile Include="Execution\SolutionChecksumObjectInfo.cs" />
     <Compile Include="Execution\ChecksumTreeCollection.cs" />
     <Compile Include="Execution\SolutionChecksumService.cs" />
+    <Compile Include="Experiments\IExperimentationService.cs" />
     <Compile Include="FindSymbols\IRemoteSymbolFinder.cs" />
     <Compile Include="FindSymbols\FindReferences\StreamingFindReferencesProgress.cs" />
     <Compile Include="FindSymbols\IStreamingFindReferencesProgress.cs" />