rules_closure violates Closure Compiler visibility for its Java packages

rules_closure/java/com/google/javascript/jscomp/ places files within the Closure Compiler package allowing it to violate package visibility and use internal APIs.

There are no guarantees about internal APIs and makes it difficult for the Closure Compiler authors to avoid breaking these rules.

Start by reviewing rules_closure/java/com/google/javascript/jscomp/ and how its files are packaged relative to Closure Compiler. Determine the intended package boundary and verify that the rules no longer rely on package-visible or internal APIs; the issue does not name specific tests or entry points.

Written by the indexing model from the issue text.