EoC should only be handled when coming from parent in RunAsync (#3540)

* Added check to only cancel dialogs in RunAsync when EoC comes from a parent bot (root or skill).
* Applied URI prefix to caller ID as per OBI spec
https://github.com/microsoft/botframework-obi/blob/master/protocols/botframework-activity/botframework-activity.md#bot-calling-skill

(cherry picked from commit 3730963)

Author: gabog

libraries/Microsoft.Bot.Builder.Dialogs/DialogExtensions.cs

@@ -38,12 +38,12 @@ public static async Task RunAsync(this Dialog dialog, ITurnContext turnContext,
             if (turnContext.TurnState.Get<IIdentity>(BotAdapter.BotIdentityKey) is ClaimsIdentity claimIdentity && SkillValidation.IsSkillClaim(claimIdentity.Claims))
             {
                 // The bot is running as a skill.
-                if (turnContext.Activity.Type == ActivityTypes.EndOfConversation && dialogContext.Stack.Any())
+                if (turnContext.Activity.Type == ActivityTypes.EndOfConversation && dialogContext.Stack.Any() && IsEocComingFromParent(turnContext))
                 {
-                    // Handle remote cancellation request if we have something in the stack.
+                    // Handle remote cancellation request from parent.
                     var activeDialogContext = GetActiveDialogContext(dialogContext);
 
-                    var remoteCancelText = "Skill was canceled by a request from the host.";
+                    var remoteCancelText = "Skill was canceled through an EndOfConversation activity from the parent.";
                     await turnContext.TraceActivityAsync($"{typeof(Dialog).Name}.RunAsync()", label: $"{remoteCancelText}", cancellationToken: cancellationToken).ConfigureAwait(false);
 
                     // Send cancellation message to the top dialog in the stack to ensure all the parents are canceled in the right order. 
@@ -90,6 +90,16 @@ public static async Task RunAsync(this Dialog dialog, ITurnContext turnContext,
             }
         }
 
+        // We should only cancel the current dialog stack if the EoC activity is coming from a parent (a root bot or another skill).
+        // When the EoC is coming back from a child, we should just process that EoC normally through the 
+        // dialog stack and let the child dialogs handle that.
+        private static bool IsEocComingFromParent(ITurnContext turnContext)
+        {
+            // To determine the direction we check callerId property which is set to the parent bot
+            // by the BotFrameworkHttpClient on outgoing requests.
+            return !string.IsNullOrWhiteSpace(turnContext.Activity.CallerId);
+        }
+
         // Recursively walk up the DC stack to find the active DC.
         private static DialogContext GetActiveDialogContext(DialogContext dialogContext)
         {

libraries/integration/Microsoft.Bot.Builder.Integration.AspNet.Core/BotFrameworkHttpClient.cs

@@ -100,7 +100,7 @@ public override async Task<InvokeResponse<T>> PostActivityAsync<T>(string fromBo
                 };
                 activity.Conversation.Id = conversationId;
                 activity.ServiceUrl = serviceUrl.ToString();
-                activity.CallerId = fromBotId;
+                activity.CallerId = $"urn:botframework:aadappid:{fromBotId}";
 
                 using (var jsonContent = new StringContent(JsonConvert.SerializeObject(activity, new JsonSerializerSettings { NullValueHandling = NullValueHandling.Ignore }), Encoding.UTF8, "application/json"))
                 {