Reland "Using R8 in place of Proguard for creating main dex list"

This is a reland of eec7c07ae2d81b16d383b5d4ec7b3a542c213303

Original change's description:
> Using R8 in place of Proguard for creating main dex list
>
> Bug: 908988
> Change-Id: I9cfe718d3754b92022c9045f860dee36c7e049bb
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1635949
> Commit-Queue: Sam Maier <smaier@chromium.org>
> Auto-Submit: Sam Maier <smaier@chromium.org>
> Reviewed-by: Eric Stevenson <estevenson@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#665957}

Bug: 908988
Change-Id: I9d535df1e642f59a639865388b90fdd066a09802
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1650373
Commit-Queue: Sam Maier <smaier@chromium.org>
Auto-Submit: Sam Maier <smaier@chromium.org>
Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#672083}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 8f7c4ee83c6c8e68c3ea028e41ff05a7a700411f
1 file changed