Android: Refactor GN templates to unify prebuilt & non-prebuilt logic

Makes it easier to add a java_annotation_processor() template

This removes main_class from java_prebuilt() in favor of using
java_binary() with a jar_path.

Bug: 792170
Cq-Include-Trybots: master.tryserver.chromium.android:android_cronet_tester;master.tryserver.chromium.mac:ios-simulator-cronet
Change-Id: I8b92addae2228398f911d9456b9c55d5ebf48529
Reviewed-on: https://chromium-review.googlesource.com/810032
Reviewed-by: Andrei Kapishnikov <kapishnikov@chromium.org>
Reviewed-by: Eric Stevenson <estevenson@chromium.org>
Commit-Queue: agrieve <agrieve@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#522220}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 4227e23c8166bcf278455bc553c3fec566c2075d
1 file changed