Remove reference to non-existent generated header.

r632842 deleted the .mojom file that generates
media_download_in_product_help.mojom.h, but forgot to remove one
reference to it.

TBR=jinsukkim@chromium.org
NOTRY=true
NOTREECHECKS=true
NOPRESUBMIT=true
BUG=715185,889682

Change-Id: I4eccc4777fd0b00f31673d9cc2ecbbf982e02d7d
Reviewed-on: https://chromium-review.googlesource.com/c/1475668
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Cr-Commit-Position: refs/heads/master@{#632847}
1 file changed