Fix memory safety issues in AppControlChannel (#151)

Author: JSUYA

flutter/shell/platform/tizen/channels/app_control.cc

@@ -67,6 +67,7 @@ AppControl::AppControl(app_control_h handle) : id_(next_id_++) {
 }
 
 AppControl::~AppControl() {
+  on_reply_ = nullptr;
   if (handle_) {
     app_control_destroy(handle_);
   }

flutter/shell/platform/tizen/channels/app_control_channel.cc

@@ -5,6 +5,7 @@
 #include "app_control_channel.h"
 
 #include <cstdint>
+#include <memory>
 #include <string>
 #include <variant>
 #include <vector>
@@ -169,15 +170,14 @@ void AppControlChannel::SendLaunchRequest(
     std::unique_ptr<MethodResult<EncodableValue>> result) {
   EncodableValueHolder<bool> wait_for_reply(arguments, "waitForReply");
   if (wait_for_reply && *wait_for_reply) {
-    auto* result_ptr = result.release();
-    auto on_reply = [result_ptr](const EncodableValue& response) {
-      result_ptr->Success(response);
-      delete result_ptr;
+    std::shared_ptr<MethodResult<EncodableValue>> result_box{std::move(result)};
+    auto on_reply = [result_box](const EncodableValue& response) {
+      result_box->Success(response);
     };
+
     AppControlResult ret = app_control->SendLaunchRequestWithReply(on_reply);
     if (!ret) {
-      result_ptr->Error(ret.code(), ret.message());
-      delete result_ptr;
+      result_box->Error(ret.code(), ret.message());
     }
   } else {
     AppControlResult ret = app_control->SendLaunchRequest();