Include JNI Java dependency on jni:setup

[HosseinYousefi]

Using JNI on Android is straightforward, as the java sources reside inside JNI's Android directory. This however is not the case for the standalone Dart projects, where the .jar file needs to be manually copied to the project. bindings_writer.dart should copy the jni.jar just as it copies dartjni.h to the src/ directory of the new JNI project. The .jar file also needs to be built if it doesn't exist or the source has changed, similar to the APISummarizer in JNIgen.

[mahesh-hegde]

What do you refer to by jni.jar? Is it in the case custom .java files are used in standalone project?

[HosseinYousefi]

To support Kotlin coroutines, I added a support class called PortContinuation to package:jni. In standalone projects, this file need to be copied into the new projects and used there. See kotlin_test.

[mahesh-hegde]

I'd suggest renaming cmake folder in jnigen/ to assets. We are going to see many this kind of files with #776 .

Edit: Nevermind it may be better to build this locally. We wouldn't want to ship Jars with source.

[HosseinYousefi]

This has been solved in dart-archive/jnigen@c951f23#diff-5d579d061f6f7b79e6722500e378c3d2cc9f4078245b483ec39228a7a35637b7.