arc: Handle non-launchable apps.

components/arc/common/app.mojom

Index: components/arc/common/app.mojom
diff --git a/components/arc/common/app.mojom b/components/arc/common/app.mojom
index 1110e41be5e13f19a61d2622d38834cb6105214f..2cd3ff154a0789b3360ccde60d032dded56cb551 100644
--- a/components/arc/common/app.mojom
+++ b/components/arc/common/app.mojom
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
-// Next MinVersion: 13
+// Next MinVersion: 14
 
 module arc.mojom;
 
@@ -91,8 +91,10 @@ interface AppHost {
   [MinVersion=1] OnPackageRemoved@3(string package_name);
 
   // Sends information about newly created task.
-  [MinVersion=4] OnTaskCreated@4(int32 task_id, string package_name,
-                                 string activity);
+  [MinVersion=4] OnTaskCreated@4(int32 task_id@0,
+                                 string package_name@1,
+                                 string activity@2,
+                                 [MinVersion=13] string? name@3);
 
   // Notifies that task has been destroyed.
   [MinVersion=4] OnTaskDestroyed@5(int32 task_id);