The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/dce5ad6ba91efb62c8df76cf455207b2f70d0cfe

commit dce5ad6ba91efb62c8df76cf455207b2f70d0cfe
Author: shaktisahu <shaktisahu@chromium.org>
Date: Mon Apr 17 23:55:30 2017

Setup download internal directory for invisible downloads

This CL sets up a download internal directory which can be used by clients
such as background fetch to store downloaded files that are not publicly
visible. Callers of DownloadManager::DownloadUrl can specify a download
path which in conjunction with transient flag will set up a pre-set path
for the downloaded file.

BUG= 710669 

Review-Url: https://codereview.chromium.org/2811173002
Cr-Commit-Position: refs/heads/master@{#465066}

[modify] https://crrev.com/dce5ad6ba91efb62c8df76cf455207b2f70d0cfe/base/android/java/src/org/chromium/base/PathUtils.java
[modify] https://crrev.com/dce5ad6ba91efb62c8df76cf455207b2f70d0cfe/base/android/path_utils.cc
[modify] https://crrev.com/dce5ad6ba91efb62c8df76cf455207b2f70d0cfe/base/android/path_utils.h
[modify] https://crrev.com/dce5ad6ba91efb62c8df76cf455207b2f70d0cfe/chrome/browser/download/download_browsertest.cc
[modify] https://crrev.com/dce5ad6ba91efb62c8df76cf455207b2f70d0cfe/content/browser/download/download_item_impl.cc