Optimize app size for line SDK

[doniwinata0309]

Is it a security issue?

If you believe you have discovered a vulnerability or have an issue related to security, please send us a mail to dl_oss_dev@linecorp.com instead of opening a public issue.

What did you do?

When implementing line sdk for login, we see significant increased on our app size. It is particulary because this rules added:

https://github.com/line/line-sdk-android/blob/master/line-sdk/consumer-proguard-rules.pro#L10
-keep class * implements android.os.Parcelable {
public static final android.os.Parcelable$Creator *;
}

This causing lot of our app class cannot be obfuscate/optimized. I already confirm it by removing/adding this rules on our app and it will keep lot of classes implementing parcelable class.

What did you expect?

This rules can be simplified to:
-keepclassmembers class * implements android.os.Parcelable {
public static final android.os.Parcelable$Creator *;
}
Or
-keepclassmembers class * implements android.os.Parcelable {
public static final android.os.Parcelable$Creator CREATOR;
}

This would saving 1-2mb on uncompressed dex size on our app.

I also find some additional library like picasso added after implemented line sdk. It would be great if line provide lite version for sdk, like line-login library.

Let me know if you need additional info. Thank you