Added notification for when language service is done updating after connect (#146)

* Added notification for when language service is done updating after connect

* Addressing feedback

* Added unit test

src/Microsoft.SqlTools.ServiceLayer/LanguageServices/Contracts/IntelliSenseReady.cs

@@ -0,0 +1,30 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+using Microsoft.SqlTools.ServiceLayer.Hosting.Protocol.Contracts;
+
+namespace Microsoft.SqlTools.ServiceLayer.LanguageServices.Contracts
+{
+    /// <summary>
+    /// Parameters sent back with an IntelliSense ready event
+    /// </summary>
+    public class IntelliSenseReadyParams
+    {
+        /// <summary>
+        /// URI identifying the text document
+        /// </summary>
+        public string OwnerUri { get; set; }
+    }
+
+    /// <summary>
+    /// Event sent when the language service is finished updating after a connection
+    /// </summary>
+    public class IntelliSenseReadyNotification
+    {
+        public static readonly
+            EventType<IntelliSenseReadyParams> Type =
+            EventType<IntelliSenseReadyParams>.Create("textDocument/intelliSenseReady");
+    }
+}

src/Microsoft.SqlTools.ServiceLayer/LanguageServices/LanguageService.cs

@@ -561,7 +561,10 @@ namespace Microsoft.SqlTools.ServiceLayer.LanguageServices
                     }
                 }  
 
-                AutoCompleteHelper.PrepopulateCommonMetadata(info, scriptInfo, this.BindingQueue);          
+                AutoCompleteHelper.PrepopulateCommonMetadata(info, scriptInfo, this.BindingQueue);
+
+                // Send a notification to signal that autocomplete is ready
+                ServiceHost.Instance.SendEvent(IntelliSenseReadyNotification.Type, new IntelliSenseReadyParams() {OwnerUri = info.OwnerUri});
             });
         }