Renames ShowPlan directories along with corresponding namespaces (#1435)

* Renames ShowPlan directories along with corresponding namespaces

* Renames ShowPlanGraphUtils to ExecutionPlanGraphUtils

* Revert "Renames ShowPlanGraphUtils to ExecutionPlanGraphUtils"

This reverts commit 5dc2696ae906598447eed7360a3f342218432b83.

* Reverts show plan tests name change.

* Renames show plan test XML files.

* Renames ported directory to ShowPlan and updates namespace accordingly

src/Microsoft.SqlTools.ServiceLayer/ExecutionPlan/ExecutionPlanService.cs

@@ -0,0 +1,83 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+using System;
+using System.Threading.Tasks;
+using Microsoft.SqlTools.Hosting.Protocol;
+using Microsoft.SqlTools.ServiceLayer.Hosting;
+
+namespace Microsoft.SqlTools.ServiceLayer.ExecutionPlan
+{
+    /// <summary>
+    /// Main class for Migration Service functionality
+    /// </summary>
+    public sealed class ExecutionPlanService : IDisposable
+    {
+        private static readonly Lazy<ExecutionPlanService> instance = new Lazy<ExecutionPlanService>(() => new ExecutionPlanService());
+
+        private bool disposed;
+
+        /// <summary>
+        /// Construct a new MigrationService instance with default parameters
+        /// </summary>
+        public ExecutionPlanService()
+        {
+        }
+
+        /// <summary>
+        /// Gets the singleton instance object
+        /// </summary>
+        public static ExecutionPlanService Instance
+        {
+            get { return instance.Value; }
+        }
+
+        /// <summary>
+        /// Service host object for sending/receiving requests/events.
+        /// Internal for testing purposes.
+        /// </summary>
+        internal IProtocolEndpoint ServiceHost
+        {
+            get;
+            set;
+        }
+
+        /// <summary>
+        /// Initializes the ShowPlan Service instance
+        /// </summary>
+        public void InitializeService(ServiceHost serviceHost)
+        {
+            this.ServiceHost = serviceHost;
+            this.ServiceHost.SetRequestHandler(GetExecutionPlanRequest.Type, HandleGetExecutionPlan);
+        }
+
+        private async Task HandleGetExecutionPlan(GetExecutionPlanParams requestParams, RequestContext<GetExecutionPlanResult> requestContext)
+        {
+            try
+            {
+                var plans = ShowPlanGraphUtils.CreateShowPlanGraph(requestParams.GraphInfo.GraphFileContent, "");
+                await requestContext.SendResult(new GetExecutionPlanResult
+                {
+                    Graphs = plans
+                });
+            }
+            catch (Exception e)
+            {
+                await requestContext.SendError(e.ToString());
+            }
+        }
+
+        /// <summary>
+        /// Disposes the ShowPlan Service
+        /// </summary>
+        public void Dispose()
+        {
+            if (!disposed)
+            {
+                disposed = true;
+            }
+        }
+    }
+}