arc: Support running Arc app in shelf

components/arc/common/app.mojom

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
-// Next MinVersion: 3
+// Next MinVersion: 4
 
 module arc;
 
 // Duplicates ui::ScaleFactor enum in order to be accessible on Android side.
 enum ScaleFactor {
   SCALE_FACTOR_NONE = 0,
   SCALE_FACTOR_100P,
   SCALE_FACTOR_125P,
   SCALE_FACTOR_133P,
   SCALE_FACTOR_140P,
@@ skipping 70 matching lines @@
                  ScaleFactor scale_factor);
 
   // Query if a given resolution can be handled by the application. Returns true
   // if it can.
   [MinVersion=1] CanHandleResolution(string package_name, string activity,
                                      ScreenRect dimension) => (bool can_handle);
 
   // Sends a request to ARC to uninstall the given package.  Error (if ever
   // happens) is ignored, and uninstall option should appear in the UI.
   [MinVersion=2] UninstallPackage(string package_name);
+
+  // Requests information about task.
+  [MinVersion=3] GetTaskInfo(int32 task_id) => (string package_name,
+                                                string activity);
 };