Add the classname to JNI method names to make them unique

Our JNI code generator generated a lot of Init(...) methods which
collided in jumbo builds. This patch adds a class name prefix to
them, and all other JNI methods, so that they have locally unique names.

TBR=erikchen@chromium.org,fgorski@chromium.org,sergeyu@chromium.org,dtrainor@chromium.org,rouslan@chromium.org,vakh@chromium.org,rogerta@chromium.org,holte@chromium.org,bajones@chromium.org

Bug: 779013
Cq-Include-Trybots: master.tryserver.chromium.android:android_cronet_tester;master.tryserver.chromium.linux:linux_site_isolation;master.tryserver.chromium.mac:ios-simulator-cronet
Change-Id: I86b6ac83c8e0a3507bd1d0efc48d625c12b4bb2b
Reviewed-on: https://chromium-review.googlesource.com/765973


Commit-Queue: Daniel Bratell <bratell@opera.com>
Reviewed-by: Daniel Bratell <bratell@opera.com>
Reviewed-by: Peter Beverloo <peter@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Reviewed-by: Rouslan Solomakhin <rouslan@chromium.org>
Reviewed-by: Sky Malice <skym@chromium.org>
Reviewed-by: Lambros Lambrou <lambroslambrou@chromium.org>
Reviewed-by: Yaron Friedman <yfriedman@chromium.org>
Reviewed-by: Luke Halliwell <halliwell@chromium.org>
Reviewed-by: Ken Rockot <rockot@chromium.org>
Reviewed-by: Richard Coles <torne@chromium.org>
Reviewed-by: Wei-Yin Chen (陳威尹) <wychen@chromium.org>
Reviewed-by: Miguel Casas <mcasas@chromium.org>
Reviewed-by: Sadrul Chowdhury <sadrul@chromium.org>
Reviewed-by: Paul Jensen <pauljensen@chromium.org>
Reviewed-by: Peter Kasting <pkasting@chromium.org>
Reviewed-by: Bernhard Bauer <bauerb@chromium.org>
Reviewed-by: agrieve <agrieve@chromium.org>
Cr-Commit-Position: refs/heads/master@{#518300}