I compiled sample NPAPI Plugin which I got from this link http://code.google.com/p/npapi-sdk/
after compiling it using NDK, I got the .so file libs/armeabi/libBasicPlugin.so
after searching on Google I came across following suggestions:
- put .so file in /data/data/com.android.browser/app_plugins/
- put .so file in /data/data/com.android.browser/assets/plugins/
but none of that works on emulator (haven't tried on device)
I tried it on Gingerbread and ICS.