reintroduce InterceptDownloadResourceThrottle for some OMA DRM downloads

reintroduce InterceptDownloadResourceThrottle for some OMA DRM downloads

For OMA DRM downloads, if download descriptor file doesn't exist, Android DownloadManager should be used.
This CL reverts some of the changes in https://codereview.chromium.org/2341643008 to intercept such downloads.

TBR=dtrainor@chromium.org,thakis@chromium.org
BUG=675559
Review-Url: https://codereview.chromium.org/2642683005
Cr-Commit-Position: refs/heads/master@{#449100}
(cherry picked from commit 1dfa16b2126e9776a3e26f00b4c767b83f2645b5)

Review-Url: https://codereview.chromium.org/2687023004 .
Cr-Commit-Position: refs/branch-heads/2987@{#408}
Cr-Branched-From: ad51088c0e8776e8dcd963dbe752c4035ba6dab6-refs/heads/master@{#444943}
Committed: https://chromium.googlesource.com/chromium/src/+/7f38b5828681175efbfac85432cd1527a68b1eff

[qinmin, 2017-02-09 17:17:55]

Description was changed from

==========
reintroduce InterceptDownloadResourceThrottle for some OMA DRM downloads

For OMA DRM downloads, if download descriptor file doesn't exist, Android
DownloadManager should be used.
This CL reverts some of the changes in
https://codereview.chromium.org/2341643008 to intercept such downloads.

TBR=dtrainor@chromium.org,thakis@chromium.org
BUG=675559

Review-Url: https://codereview.chromium.org/2642683005
Cr-Commit-Position: refs/heads/master@{#449100}
(cherry picked from commit 1dfa16b2126e9776a3e26f00b4c767b83f2645b5)
==========

to

==========
reintroduce InterceptDownloadResourceThrottle for some OMA DRM downloads

For OMA DRM downloads, if download descriptor file doesn't exist, Android
DownloadManager should be used.
This CL reverts some of the changes in
https://codereview.chromium.org/2341643008 to intercept such downloads.

TBR=dtrainor@chromium.org,thakis@chromium.org
BUG=675559

Review-Url: https://codereview.chromium.org/2642683005
Cr-Commit-Position: refs/heads/master@{#449100}
(cherry picked from commit 1dfa16b2126e9776a3e26f00b4c767b83f2645b5)

Review-Url: https://codereview.chromium.org/2687023004 .
Cr-Commit-Position: refs/branch-heads/2987@{#408}
Cr-Branched-From:
ad51088c0e8776e8dcd963dbe752c4035ba6dab6-refs/heads/master@{#444943}
Committed:
https://chromium.googlesource.com/chromium/src/+/7f38b5828681175efbfac85432cd...
==========

[qinmin, 2017-02-09 17:17:56]

Committed patchset #1 (id:1) manually as
7f38b5828681175efbfac85432cd1527a68b1eff (presubmit successful).