HAve 'ObjectBrowser-FindRefs' go through the new streaming FindReferences codepath.

src/EditorFeatures/Core/FindUsages/AbstractFindUsagesService.ProgressAdapter.cs

@@ -38,7 +38,7 @@ public Task ReportProgressAsync(int current, int maximum)
         /// <summary>
         /// Forwards IFindReferencesProgress calls to an IFindUsagesContext instance.
         /// </summary>
-        private class FindReferencesProgressAdapter : ForegroundThreadAffinitizedObject, IStreamingFindReferencesProgress
+        internal class FindReferencesProgressAdapter : ForegroundThreadAffinitizedObject, IStreamingFindReferencesProgress
         {
             private readonly Solution _solution;
             private readonly IFindUsagesContext _context;

src/EditorFeatures/Core/FindUsages/AbstractFindUsagesService.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.Collections.Immutable;
+using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.FindSymbols;
 using Microsoft.CodeAnalysis.FindUsages;
@@ -87,9 +88,13 @@ public async Task FindImplementationsAsync(Document document, int position, IFin
                 return null;
             }
 
-            var symbol = symbolAndProject?.symbol;
-            var project = symbolAndProject?.project;
+            return await FindSymbolReferencesAsync(
+                context, symbolAndProject?.symbol, symbolAndProject?.project, cancellationToken).ConfigureAwait(false);
+        }
 
+        public static async Task<FindReferencesProgressAdapter> FindSymbolReferencesAsync(
+            IFindUsagesContext context, ISymbol symbol, Project project, CancellationToken cancellationToken)
+        {
             context.SetSearchTitle(string.Format(EditorFeaturesResources._0_references,
                 FindUsagesHelpers.GetDisplayName(symbol)));
 

src/VisualStudio/Core/Def/Implementation/Library/ObjectBrowser/AbstractObjectBrowserLibraryManager.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.Collections.Generic;
 using System.Diagnostics;
+using System.Linq;
 using System.Text;
 using System.Threading;
 using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.Editor;
+using Microsoft.CodeAnalysis.Editor.FindUsages;
+using Microsoft.CodeAnalysis.Editor.Host;
 using Microsoft.CodeAnalysis.ErrorReporting;
 using Microsoft.VisualStudio.ComponentModelHost;
 using Microsoft.VisualStudio.LanguageServices.Implementation.Library.ObjectBrowser.Lists;
@@ -33,7 +38,13 @@ internal abstract partial class AbstractObjectBrowserLibraryManager : AbstractLi
         private AbstractListItemFactory _listItemFactory;
         private object _classMemberGate = new object();
 
-        protected AbstractObjectBrowserLibraryManager(string languageName, Guid libraryGuid, __SymbolToolLanguage preferredLanguage, IServiceProvider serviceProvider)
+        private readonly IEnumerable<Lazy<IStreamingFindUsagesPresenter>> _streamingPresenters;
+
+        protected AbstractObjectBrowserLibraryManager(
+            string languageName, 
+            Guid libraryGuid, 
+            __SymbolToolLanguage preferredLanguage, 
+            IServiceProvider serviceProvider)
             : base(libraryGuid, serviceProvider)
         {
             _languageName = languageName;
@@ -43,6 +54,8 @@ protected AbstractObjectBrowserLibraryManager(string languageName, Guid libraryG
             this.Workspace = componentModel.GetService<VisualStudioWorkspace>();
             this.LibraryService = this.Workspace.Services.GetLanguageServices(languageName).GetService<ILibraryService>();
             this.Workspace.WorkspaceChanged += OnWorkspaceChanged;
+
+            this._streamingPresenters = componentModel.DefaultExportProvider.GetExports<IStreamingFindUsagesPresenter>();
         }
 
         internal abstract AbstractDescriptionBuilder CreateDescriptionBuilder(
@@ -481,24 +494,15 @@ protected override bool TryExec(Guid commandGroup, uint commandId)
                 switch (commandId)
                 {
                     case (uint)VSConstants.VSStd97CmdID.FindReferences:
+                        var streamingPresenter = GetStreamingPresenter();
                         var symbolListItem = _activeListItem as SymbolListItem;
-                        if (symbolListItem != null)
+                        if (streamingPresenter != null && symbolListItem?.ProjectId != null)
                         {
-                            var projectId = symbolListItem.ProjectId;
-                            if (projectId != null)
+                            var project = this.Workspace.CurrentSolution.GetProject(symbolListItem.ProjectId);
+                            if (project != null)
                             {
-                                var project = this.Workspace.CurrentSolution.GetProject(projectId);
-                                if (project != null)
-                                {
-                                    var compilation = project
-                                        .GetCompilationAsync(CancellationToken.None)
-                                        .WaitAndGetResult(CancellationToken.None);
-
-                                    var symbol = symbolListItem.ResolveSymbol(compilation);
-
-                                    this.Workspace.TryFindAllReferences(symbol, project, CancellationToken.None);
-                                    return true;
-                                }
+                                FindReferences(streamingPresenter, symbolListItem, project);
+                                return true;
                             }
                         }
 
@@ -508,5 +512,51 @@ protected override bool TryExec(Guid commandGroup, uint commandId)
 
             return false;
         }
+
+        private IStreamingFindUsagesPresenter GetStreamingPresenter()
+        {
+            try
+            {
+                return _streamingPresenters.FirstOrDefault()?.Value;
+            }
+            catch
+            {
+                return null;
+            }
+        }
+
+        private async void FindReferences(
+            IStreamingFindUsagesPresenter presenter, SymbolListItem symbolListItem, Project project)
+        {
+            try
+            {
+                // Let the presented know we're starting a search.  It will give us back
+                // the context object that the FAR service will push results into.
+                var context = presenter.StartSearch(
+                    EditorFeaturesResources.Find_References, supportsReferences: true);
+
+                var cancellationToken = context.CancellationToken;
+
+                // Fire and forget the work to go get references.
+                var compilation = await project.GetCompilationAsync(cancellationToken).ConfigureAwait(false);
+                var symbol = symbolListItem.ResolveSymbol(compilation);
+
+                await AbstractFindUsagesService.FindSymbolReferencesAsync(
+                    context, symbol, project, cancellationToken).ConfigureAwait(false);
+
+                // Note: we don't need to put this in a finally.  The only time we might not hit
+                // this is if cancellation or another error gets thrown.  In the former case,
+                // that means that a new search has started.  We don't care about telling the
+                // context it has completed.  In the latter case something wrong has happened
+                // and we don't want to run any more code in this particular context.
+                await context.OnCompletedAsync().ConfigureAwait(false);
+            }
+            catch (OperationCanceledException)
+            {
+            }
+            catch (Exception e) when (FatalError.ReportWithoutCrash(e))
+            {
+            }
+        }
     }
-}
+}
\ No newline at end of file

src/VisualStudio/Core/Impl/RoslynVisualStudioWorkspace.cs

@@ -6,23 +6,17 @@
 using System.Linq;
 using System.Threading;
 using Microsoft.CodeAnalysis;
-using Microsoft.CodeAnalysis.Editor.FindUsages;
 using Microsoft.CodeAnalysis.Editor.GoToDefinition;
 using Microsoft.CodeAnalysis.Editor.Host;
 using Microsoft.CodeAnalysis.Editor.Undo;
 using Microsoft.CodeAnalysis.FindSymbols;
-using Microsoft.CodeAnalysis.FindUsages;
-using Microsoft.CodeAnalysis.GeneratedCodeRecognition;
 using Microsoft.CodeAnalysis.Options;
 using Microsoft.CodeAnalysis.Shared.Extensions;
-using Microsoft.VisualStudio.ComponentModelHost;
 using Microsoft.VisualStudio.Composition;
-using Microsoft.VisualStudio.LanguageServices.Implementation;
 using Microsoft.VisualStudio.LanguageServices.Implementation.CodeModel;
 using Microsoft.VisualStudio.LanguageServices.Implementation.Interop;
 using Microsoft.VisualStudio.LanguageServices.Implementation.Library.ObjectBrowser.Lists;
 using Microsoft.VisualStudio.LanguageServices.Implementation.ProjectSystem;
-using Microsoft.VisualStudio.Shell;
 using Roslyn.Utilities;
 
 namespace Microsoft.VisualStudio.LanguageServices
@@ -32,18 +26,15 @@ namespace Microsoft.VisualStudio.LanguageServices
     internal class RoslynVisualStudioWorkspace : VisualStudioWorkspaceImpl
     {
         private readonly IEnumerable<Lazy<IStreamingFindUsagesPresenter>> _streamingPresenters;
-        private readonly IEnumerable<Lazy<IDefinitionsAndReferencesPresenter>> _referencedSymbolsPresenters;
 
         [ImportingConstructor]
         private RoslynVisualStudioWorkspace(
             ExportProvider exportProvider,
             [ImportMany] IEnumerable<Lazy<IStreamingFindUsagesPresenter>> streamingPresenters,
-            [ImportMany] IEnumerable<Lazy<IDefinitionsAndReferencesPresenter>> referencedSymbolsPresenters,
             [ImportMany] IEnumerable<IDocumentOptionsProviderFactory> documentOptionsProviderFactories)
             : base(exportProvider.AsExportProvider())
         {
             _streamingPresenters = streamingPresenters;
-            _referencedSymbolsPresenters = referencedSymbolsPresenters;
 
             foreach (var providerFactory in documentOptionsProviderFactories)
             {
@@ -203,44 +194,15 @@ private static bool TryResolveSymbol(ISymbol symbol, Project project, Cancellati
 
         public override bool TryFindAllReferences(ISymbol symbol, Project project, CancellationToken cancellationToken)
         {
-            if (!_referencedSymbolsPresenters.Any())
-            {
-                return false;
-            }
-
-            if (!TryResolveSymbol(symbol, project, cancellationToken, out var searchSymbol, out var searchProject))
-            {
-                return false;
-            }
-
-            var searchSolution = searchProject.Solution;
-
-            var result = SymbolFinder
-                .FindReferencesAsync(searchSymbol, searchSolution, cancellationToken)
-                .WaitAndGetResult(cancellationToken).ToList();
-
-            if (result != null)
-            {
-                DisplayReferencedSymbols(searchSolution, result);
-                return true;
-            }
-
+            // Legacy API.  Previously used by ObjectBrowser to support 'FindRefs' off of an
+            // object browser item.  Now ObjectBrowser goes through the streaming-FindRefs system.
             return false;
         }
 
-        public override void DisplayReferencedSymbols(
-            Solution solution, IEnumerable<ReferencedSymbol> referencedSymbols)
+        public override void DisplayReferencedSymbols(Solution solution, IEnumerable<ReferencedSymbol> referencedSymbols)
         {
-            var service = this.Services.GetService<IDefinitionsAndReferencesFactory>();
-            var definitionsAndReferences = service.CreateDefinitionsAndReferences(
-                solution, referencedSymbols,
-                includeHiddenLocations: false, cancellationToken: CancellationToken.None);
-
-            foreach (var presenter in _referencedSymbolsPresenters)
-            {
-                presenter.Value.DisplayResult(definitionsAndReferences);
-                return;
-            }
+            // Legacy API.  Previously used by ObjectBrowser to support 'FindRefs' off of an
+            // object browser item.  Now ObjectBrowser goes through the streaming-FindRefs system.
         }
 
         internal override object GetBrowseObject(SymbolListItem symbolListItem)