Make Provider's DBHelper class and variable protected to facilitate sub-classing

I needed to populate a table after database creation, so I wanted to do this via a sub-class of the Provider. My sub-class overrides onCreate, and sub-classes DbHelper so it can also override onCreate(SQLiteDatabase). Then after super.onCreate is called, I can populate the table. By allowing sub-classing, the files can be generated again in the future and my sub-class is still intact.