Merge "adb: avoid sign extension of shell return code." am: b5ac15a9

                    callback->OnStderr(buffer_ptr, length);

                    break;

                case ShellProtocol::kIdExit:

                    exit_code = protocol->data()[0];

                    // data() returns a char* which doesn't have defined signedness.

                    // Cast to uint8_t to prevent 255 from being sign extended to INT_MIN,

                    // which doesn't get truncated on Windows.

                    exit_code = static_cast<uint8_t>(protocol->data()[0]);

                    continue;

                default:

                    continue;