We need to prune from two places on Android:
- Notifications
- DownloadManager additions

Add nancygao@ for PRD doc. I'll start to remove file names from download notification and Android DownloadManager hook for incognito mode.

Do we want to hide the download from android DownloadManager for incognito mode?

Currently the android download id is used in couple of places, like the inforbar for other apps to open, or oma downloads.

On Android O, we can't actually hide the download in incognito mode, since android download manager will scan the disk I believe.

Also when we throw empty file names and file path, it will return invalid android download id, which will fail the download.

Screenshot that download status text as title when there is no file name.

Deleted: screencap.png 458 KB

	screencap.png 458 KB View Download

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/e37cd83a8db27687ece66d3236f0b8c4ab03444b

commit e37cd83a8db27687ece66d3236f0b8c4ab03444b
Author: Xing Liu <xingliu@chromium.org>
Date: Fri Sep 14 02:11:12 2018

Android Download notification: Don't show file details for incognito mode.

In incognito mode, Android download notification no longer shows file
names and file size for privacy reasons. We also show "Incognito tab" as
subtext to inform the user that they are using incognito mode.

Also plumbs isOffTheRecord for failed download notifications, so failed
download notification will not show file details as well.

Bug:  880359 
Change-Id: I85aaf73db8ad566aad912f0d826213777dec90f2
Reviewed-on: https://chromium-review.googlesource.com/1214076
Commit-Queue: Xing Liu <xingliu@chromium.org>
Reviewed-by: Min Qin <qinmin@chromium.org>
Reviewed-by: David Trainor <dtrainor@chromium.org>
Cr-Commit-Position: refs/heads/master@{#591264}
[modify] https://crrev.com/e37cd83a8db27687ece66d3236f0b8c4ab03444b/chrome/android/java/src/org/chromium/chrome/browser/download/DownloadNotificationFactory.java
[modify] https://crrev.com/e37cd83a8db27687ece66d3236f0b8c4ab03444b/chrome/android/java/src/org/chromium/chrome/browser/download/DownloadNotificationService2.java
[modify] https://crrev.com/e37cd83a8db27687ece66d3236f0b8c4ab03444b/chrome/android/java/src/org/chromium/chrome/browser/download/SystemDownloadNotifier2.java
[modify] https://crrev.com/e37cd83a8db27687ece66d3236f0b8c4ab03444b/chrome/android/java/strings/android_chrome_strings.grd
[modify] https://crrev.com/e37cd83a8db27687ece66d3236f0b8c4ab03444b/chrome/android/javatests/src/org/chromium/chrome/browser/download/MockDownloadNotificationService2.java

The text for this change (along with other notifications) was discussed with the UI team and here is their final approval:
https://docs.google.com/presentation/d/1K6mh-NO1DXxBm2Lou4RJiteGoybQo_n7pCay5BPOGeo

It seems that the implementation quite aligns with that.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/2392d1812ecafd1e20c283f0b35f0c29ba68e57d

commit 2392d1812ecafd1e20c283f0b35f0c29ba68e57d
Author: Rayan Kanso <rayankans@chromium.org>
Date: Fri Sep 21 17:04:49 2018

[Android Download Notification] Remove icons in incognito

Strip out non-default download notification icons when in incognito mode
for privacy reasons.

Bug:  880359 
Change-Id: I92a06923672e4f581389f56e17a2f9c0d05b8bc3
Reviewed-on: https://chromium-review.googlesource.com/1233753
Reviewed-by: David Trainor <dtrainor@chromium.org>
Reviewed-by: Xing Liu <xingliu@chromium.org>
Commit-Queue: Rayan Kanso <rayankans@chromium.org>
Cr-Commit-Position: refs/heads/master@{#593235}
[modify] https://crrev.com/2392d1812ecafd1e20c283f0b35f0c29ba68e57d/chrome/android/java/src/org/chromium/chrome/browser/download/DownloadNotificationFactory.java
[modify] https://crrev.com/2392d1812ecafd1e20c283f0b35f0c29ba68e57d/chrome/android/java/src/org/chromium/chrome/browser/download/DownloadNotificationService.java
[modify] https://crrev.com/2392d1812ecafd1e20c283f0b35f0c29ba68e57d/chrome/android/java/src/org/chromium/chrome/browser/download/DownloadNotificationService2.java