Enable jumbo support in media/base

Building //media takes around 23 CPU minutes. A experimental
branch showed that this could be reduced, by using jumbo,
to around 9 CPU minutes. media/base is the second largest part
of media and takes around 3.1 CPU minutes to compile without
jumbo.

This commit enables jumbo for media/base.

Bug: 867350
Change-Id: Ie2dae0a65bfc596b30339712a39cab321e293f48
Reviewed-on: https://chromium-review.googlesource.com/1150037
Reviewed-by: Chrome Cunningham (In Paris) <chcunningham@chromium.org>
Commit-Queue: Oscar Johansson <oscarj@opera.com>
Cr-Commit-Position: refs/heads/master@{#578305}
5 files changed