Reland "Fix an issue that ResourceDownloader was never deleted on download completion"

This reverts commit 9faf0129433836d06b0a7113a61332b5b7090cd3.

Reason for revert: <INSERT REASONING HERE>

Original change's description:
> Revert "Fix an issue that ResourceDownloader was never deleted on download completion"
> 
> This reverts commit e0b12de09e77d5954ace778522cf1a41c90f13aa.
> 
> Reason for revert: The Cl probably introduced flakiness in multiple download related tests (https://crbug.com/864922)
> 
> Original change's description:
> > Fix an issue that ResourceDownloader was never deleted on download completion
> > 
> > This CL calls the InProgressDownloadManager to delete ResourceDownloader
> > after response is completed.
> > It also fixes the issue when download is cancelled.
> > 
> > BUG=864189
> > 
> > Change-Id: I184d5faaace90f49874e45b4126a0a9821fdced7
> > Reviewed-on: https://chromium-review.googlesource.com/1138676
> > Commit-Queue: Min Qin <qinmin@chromium.org>
> > Reviewed-by: Xing Liu <xingliu@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#575882}
> 
> TBR=qinmin@chromium.org,shaktisahu@chromium.org,xingliu@chromium.org
> 
> Change-Id: I669a69fc135547508b44ccc8150847cc5824b2ec
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Bug: 864189
> Reviewed-on: https://chromium-review.googlesource.com/1141684
> Reviewed-by: Christian Dullweber <dullweber@chromium.org>
> Commit-Queue: Christian Dullweber <dullweber@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#575981}

TBR=qinmin@chromium.org,shaktisahu@chromium.org,dullweber@chromium.org,xingliu@chromium.org

Change-Id: I11012d0bf159f4944d69cc13881180db9ed98d7e
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 864189
Reviewed-on: https://chromium-review.googlesource.com/1142171
Reviewed-by: Min Qin <qinmin@chromium.org>
Commit-Queue: Min Qin <qinmin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#576190}
11 files changed