Fix NPE when logging a WTF in unknown process

        final StringBuilder sb = new StringBuilder(1024);

        appendDropBoxProcessHeaders(process, processName, sb);

        if (process != null) {

            sb.append("Foreground: ")

                    .append(process.isInterestingToUserLocked() ? "Yes" : "No")

                    .append("\n");

        }

        if (activity != null) {

            sb.append("Activity: ").append(activity.shortComponentName).append("\n");

        }