Reland "Android: Delete in-product help for media download code"

This is a reland of b011f9b2c886d20f519cc2208e3d577a40098d7c

FindIt was too aggressive and auto-reverted r632842, as r632848,
which results in a broken tree because it is incompatible with
r632847 which already fixed the build.

TBR=jinsukkim@chromium.org
NOTRY=true
NOTREECHECKS=true
NOPRESUBMIT=true

Original change's description:
> Android: Delete in-product help for media download code
>
> In-product help system was determined not to be launched.
> This CL reverts https://crrev.com/2943983003 which added
> the functionality for media download.
>
> Bug: 715185, 889682
> Change-Id: I7478eb2438023febd894560b18b6c380f81577e2
> Reviewed-on: https://chromium-review.googlesource.com/c/1367065
> Reviewed-by: David Trainor <dtrainor@chromium.org>
> Reviewed-by: Stephen Chenney <schenney@chromium.org>
> Reviewed-by: Daniel Cheng <dcheng@chromium.org>
> Reviewed-by: Mounir Lamouri <mlamouri@chromium.org>
> Reviewed-by: Pavel Feldman <pfeldman@chromium.org>
> Commit-Queue: Jinsuk Kim <jinsukkim@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#632842}

Bug: 715185, 889682
Change-Id: I73be467fcb49cb5e08ccf4d35737c6bff9ce9019
Reviewed-on: https://chromium-review.googlesource.com/c/1476083
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
Cr-Commit-Position: refs/heads/master@{#632849}
37 files changed