Revert 282243 "Fix an issue that android Download Manager doesn'..."
> Fix an issue that android Download Manager doesn't handle OMA files correctly
>
> For OMA files, it looks like that android download manager cannot correctly download it.
> Some of the files cannot be downloaded, and some of the files downloaded has different binary content as the ones downloaed on chrome desktop.
> Bypass android download manager for OMA mime types.
>
> BUG=382698
>
> Review URL: https://codereview.chromium.org/
331143010
TBR=tedchoc@chromium.org
BUG=382698
Review URL: https://codereview.chromium.org/
567733002
Cr-Commit-Position: refs/heads/master@{#294538}