Generate GEN_JNI.java for every .apk

This is part of a better scheme for calling Java->Native
where all native methods are hidden behind interfaces,
and exist within a single "GEN_JNI.java" generated file.
See bug for more details.

Bug: 898261
Change-Id: I1fd7a9f162cb2853a2dfcd62ffcdebe909cb40e1
Reviewed-on: https://chromium-review.googlesource.com/c/1315808
Commit-Queue: Eric Stevenson <estevenson@chromium.org>
Reviewed-by: Misha Efimov <mef@chromium.org>
Reviewed-by: Tibor Goldschwendt <tiborg@chromium.org>
Reviewed-by: Eric Stevenson <estevenson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#608614}
9 files changed