Merge "Nullptr check for getActiveConfig() in doDump()"

    if (const auto displayId = getInternalDisplayIdLocked();

        displayId && getHwComposer().isConnected(*displayId)) {

        const auto activeConfig = getHwComposer().getActiveConfig(*displayId);

        std::string fps, xDpi, yDpi;

        if (activeConfig) {

            fps = std::to_string(1e9 / getHwComposer().getDisplayVsyncPeriod(*displayId)) + " fps";

            xDpi = activeConfig->getDpiX();

            yDpi = activeConfig->getDpiY();

        } else {

            fps = "unknown";

            xDpi = "unknown";

            yDpi = "unknown";

        }

        StringAppendF(&result,

                      "  refresh-rate              : %f fps\n"

                      "  x-dpi                     : %f\n"

                      "  y-dpi                     : %f\n",

                      1e9 / getHwComposer().getDisplayVsyncPeriod(*displayId),

                      activeConfig->getDpiX(), activeConfig->getDpiY());

                      "  refresh-rate              : %s\n"

                      "  x-dpi                     : %s\n"

                      "  y-dpi                     : %s\n",

                      fps.c_str(), xDpi.c_str(), yDpi.c_str());

    }

    StringAppendF(&result, "  transaction time: %f us\n", inTransactionDuration / 1000.0);