arc: Set custom icon in shelf for ARC apps.

components/arc/test/fake_app_instance.h

Index: components/arc/test/fake_app_instance.h
diff --git a/components/arc/test/fake_app_instance.h b/components/arc/test/fake_app_instance.h
index 7eab7891450820d40d01e589d1908913e20428ac..52e287ab11708aa6d03b9e414b073002855a5b51 100644
--- a/components/arc/test/fake_app_instance.h
+++ b/components/arc/test/fake_app_instance.h
@@ -121,6 +121,9 @@ class FakeAppInstance : public mojom::AppInstance {
   void SendTaskCreated(int32_t taskId,
                        const mojom::AppInfo& app,
                        const std::string& intent);
+  void SendTaskDescription(int32_t taskId,
+                           const std::string& label,
+                           const std::string& icon_png_data_as_string);
   void SendTaskDestroyed(int32_t taskId);
   bool GenerateAndSendIcon(const mojom::AppInfo& app,
                            mojom::ScaleFactor scale_factor,