Use UIContext_Git to initialize PR status bar

We no longer need to use `IVSGitExt` to initialize the PR status bar when there is an active Git repository.

Author: jcansdale

src/GitHub.InlineReviews/PullRequestStatusBarPackage.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Threading;
 using System.Runtime.InteropServices;
+using GitHub.Helpers;
 using GitHub.Services;
 using GitHub.VisualStudio;
 using GitHub.InlineReviews.Services;
@@ -11,7 +12,7 @@ namespace GitHub.InlineReviews
 {
     [Guid(Guids.PullRequestStatusPackageId)]
     [PackageRegistration(UseManagedResourcesOnly = true, AllowsBackgroundLoading = true)]
-    [ProvideAutoLoad(Guids.GitSccProviderId, PackageAutoLoadFlags.BackgroundLoad)]
+    [ProvideAutoLoad(Guids.UIContext_Git, PackageAutoLoadFlags.BackgroundLoad)]
     public class PullRequestStatusBarPackage : AsyncPackage
     {
         /// <summary>
@@ -21,9 +22,11 @@ protected override async Task InitializeAsync(CancellationToken cancellationToke
         {
             var usageTracker = (IUsageTracker)await GetServiceAsync(typeof(IUsageTracker));
             var serviceProvider = (IGitHubServiceProvider)await GetServiceAsync(typeof(IGitHubServiceProvider));
-            var gitExt = (IVSGitExt)await GetServiceAsync(typeof(IVSGitExt));
+            var barManager = new PullRequestStatusBarManager(usageTracker, serviceProvider);
 
-            new PullRequestStatusBarManager(gitExt, usageTracker, serviceProvider);
+            // await ThreadingHelper.SwitchToMainThreadAsync() won't return until after a solution
+            // has been loaded. We're using the following instead as a workaround.
+            await ThreadingHelper.MainThreadDispatcher.InvokeAsync(() => barManager.StartShowingStatus());
         }
     }
 }

src/GitHub.InlineReviews/Services/PullRequestStatusBarManager.cs

@@ -21,33 +21,19 @@ public class PullRequestStatusBarManager
         static readonly ILogger log = LogManager.ForContext<PullRequestStatusBarManager>();
         const string StatusBarPartName = "PART_SccStatusBarHost";
 
-        readonly IVSGitExt gitExt;
         readonly IUsageTracker usageTracker;
         readonly IGitHubServiceProvider serviceProvider;
 
         IPullRequestSessionManager pullRequestSessionManager;
 
         [ImportingConstructor]
-        public PullRequestStatusBarManager(IVSGitExt gitExt, IUsageTracker usageTracker, IGitHubServiceProvider serviceProvider)
+        public PullRequestStatusBarManager(IUsageTracker usageTracker, IGitHubServiceProvider serviceProvider)
         {
-            this.gitExt = gitExt;
             this.usageTracker = usageTracker;
             this.serviceProvider = serviceProvider;
-
-            OnActiveRepositoriesChanged();
-            gitExt.ActiveRepositoriesChanged += OnActiveRepositoriesChanged;
-        }
-
-        void OnActiveRepositoriesChanged()
-        {
-            if (gitExt.ActiveRepositories.Count > 0)
-            {
-                gitExt.ActiveRepositoriesChanged -= OnActiveRepositoriesChanged;
-                Application.Current.Dispatcher.Invoke(() => StartShowingStatus());
-            }
         }
 
-        void StartShowingStatus()
+        public void StartShowingStatus()
         {
             try
             {