The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/9b87ece5135008a0a046a7b2edf4436d60183144

commit 9b87ece5135008a0a046a7b2edf4436d60183144
Author: qinmin <qinmin@chromium.org>
Date: Fri Apr 15 19:39:54 2016

Make notification high priority While download is in progress

Android only show action buttons when notification is on top
of the notification drawer.
By setting priority to high, we move the download progress
notification to the top drawer.
As a result, user can see the action buttons and pause/cancel the active
download.

This UI change is per discussion with rolfe@ and sidv@.

BUG= 603229 

Review URL: https://codereview.chromium.org/1889443003

Cr-Commit-Position: refs/heads/master@{#387674}

[modify] https://crrev.com/9b87ece5135008a0a046a7b2edf4436d60183144/chrome/android/java/src/org/chromium/chrome/browser/download/DownloadNotificationService.java

Your change meets the bar and is auto-approved for M51 (branch: 2704)

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/d47b3994afdddf2e3d40f510b8c56935c3fcd5ce

commit d47b3994afdddf2e3d40f510b8c56935c3fcd5ce
Author: Min Qin <qinmin@chromium.org>
Date: Fri Apr 15 21:28:43 2016

Make notification high priority While download is in progress

Android only show action buttons when notification is on top
of the notification drawer.
By setting priority to high, we move the download progress
notification to the top drawer.
As a result, user can see the action buttons and pause/cancel the active
download.

This UI change is per discussion with rolfe@ and sidv@.

TBR=dtrainor@chromium.org
BUG= 603229 

Review URL: https://codereview.chromium.org/1889443003

Cr-Commit-Position: refs/heads/master@{#387674}
(cherry picked from commit 9b87ece5135008a0a046a7b2edf4436d60183144)

Review URL: https://codereview.chromium.org/1893613003 .

Cr-Commit-Position: refs/branch-heads/2704@{#81}
Cr-Branched-From: 6e53600def8f60d8c632fadc70d7c1939ccea347-refs/heads/master@{#386251}

[modify] https://crrev.com/d47b3994afdddf2e3d40f510b8c56935c3fcd5ce/chrome/android/java/src/org/chromium/chrome/browser/download/DownloadNotificationService.java