These were enabled in https://chromium-review.googlesource.com/c/chromium/src/+/965921. Will proceed to revert the CL.

Failure log -


[ RUN      ] WebViewTests/WebViewTest.DownloadCookieIsolation_CrossSession/0
Xlib:  extension "RANDR" missing on display ":99".
[5306:5526:0316/171153.013317:ERROR:bus.cc(394)] Failed to connect to the bus: Could not parse server address: Unknown address type (examples of valid types are "tcp" and on UNIX "unix")
[5306:5306:0316/171153.025794:WARNING:password_store_factory.cc(240)] Using basic (unencrypted) store for password storage. See https://chromium.googlesource.com/chromium/src/+/master/docs/linux_password_storage.md for more information about password storage options.
(browser_tests:5306): LIBDBUSMENU-GLIB-WARNING **: Unable to get session bus: Unknown or unsupported transport 'disabled' for address 'disabled:'
../../chrome/browser/apps/guest_view/web_view_browsertest.cc:3152: Failure
Expected equality of these values:
  download::DownloadItem::COMPLETE
    Which is: 1
  succeeded_download->GetState()
    Which is: 3
[  FAILED  ] WebViewTests/WebViewTest.DownloadCookieIsolation_CrossSession/0, where GetParam() = false (506 ms)
[ RUN      ] WebViewTests/WebViewTest.DownloadCookieIsolation_CrossSession/0
Xlib:  extension "RANDR" missing on display ":99".
[6561:6591:0316/171156.526732:ERROR:bus.cc(394)] Failed to connect to the bus: Could not parse server address: Unknown address type (examples of valid types are "tcp" and on UNIX "unix")
[6561:6561:0316/171156.534577:WARNING:password_store_factory.cc(240)] Using basic (unencrypted) store for password storage. See https://chromium.googlesource.com/chromium/src/+/master/docs/linux_password_storage.md for more information about password storage options.
(browser_tests:6561): LIBDBUSMENU-GLIB-WARNING **: Unable to get session bus: Unknown or unsupported transport 'disabled' for address 'disabled:'
../../chrome/browser/apps/guest_view/web_view_browsertest.cc:3152: Failure
Expected equality of these values:
  download::DownloadItem::COMPLETE
    Which is: 1
  succeeded_download->GetState()
    Which is: 3
[  FAILED  ] WebViewTests/WebViewTest.DownloadCookieIsolation_CrossSession/0, where GetParam() = false (385 ms)
[ RUN      ] WebViewTests/WebViewTest.DownloadCookieIsolation_CrossSession/0
Xlib:  extension "RANDR" missing on display ":99".
[6788:6818:0316/171157.708673:ERROR:bus.cc(394)] Failed to connect to the bus: Could not parse server address: Unknown address type (examples of valid types are "tcp" and on UNIX "unix")
[6788:6788:0316/171157.719735:WARNING:password_store_factory.cc(240)] Using basic (unencrypted) store for password storage. See https://chromium.googlesource.com/chromium/src/+/master/docs/linux_password_storage.md for more information about password storage options.
(browser_tests:6788): LIBDBUSMENU-GLIB-WARNING **: Unable to get session bus: Unknown or unsupported transport 'disabled' for address 'disabled:'
../../chrome/browser/apps/guest_view/web_view_browsertest.cc:3152: Failure
Expected equality of these values:
  download::DownloadItem::COMPLETE
    Which is: 1
  succeeded_download->GetState()
    Which is: 3
[  FAILED  ] WebViewTests/WebViewTest.DownloadCookieIsolation_CrossSession/0, where GetParam() = false (375 ms)
[ RUN      ] WebViewTests/WebViewTest.DownloadCookieIsolation_CrossSession/0
Xlib:  extension "RANDR" missing on display ":99".
[7015:7045:0316/171158.880956:ERROR:bus.cc(394)] Failed to connect to the bus: Could not parse server address: Unknown address type (examples of valid types are "tcp" and on UNIX "unix")
[7015:7015:0316/171158.889212:WARNING:password_store_factory.cc(240)] Using basic (unencrypted) store for password storage. See https://chromium.googlesource.com/chromium/src/+/master/docs/linux_password_storage.md for more information about password storage options.
(browser_tests:7015): LIBDBUSMENU-GLIB-WARNING **: Unable to get session bus: Unknown or unsupported transport 'disabled' for address 'disabled:'
../../chrome/browser/apps/guest_view/web_view_browsertest.cc:3152: Failure
Expected equality of these values:
  download::DownloadItem::COMPLETE
    Which is: 1
  succeeded_download->GetState()
    Which is: 3
[  FAILED  ] WebViewTests/WebViewTest.DownloadCookieIsolation_CrossSession/0, where GetParam() = false (382 ms)

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/7a8a322ad719a0503ba7e8452fad79b6b79cbd04

commit 7a8a322ad719a0503ba7e8452fad79b6b79cbd04
Author: Karan Bhatia <karandeepb@chromium.org>
Date: Sat Mar 17 02:42:10 2018

Revert "Fix webview tag's using an on-disk directory with the network service enabled."

This reverts commit 1f76c8484593c804889e33905bf1ba76cea5108b.

Reason for revert: WebViewTests/WebViewTest.DownloadCookieIsolation_CrossSession/0 is flaky with network service.

Original change's description:
> Fix webview tag's using an on-disk directory with the network service enabled.
> 
> Bug:  769401 
> Cq-Include-Trybots: master.tryserver.chromium.linux:linux_mojo
> Change-Id: Ia9ad46583b00f88631eccbc65c23cf6864134f26
> Reviewed-on: https://chromium-review.googlesource.com/965921
> Reviewed-by: Matt Menke <mmenke@chromium.org>
> Commit-Queue: John Abd-El-Malek <jam@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#543837}

TBR=creis@chromium.org,jam@chromium.org,mmenke@chromium.org

Bug:  769401 ,  822999 
Change-Id: I0feb3dcddc8c7a767b1026c9f3a206419ab89225
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_mojo
Reviewed-on: https://chromium-review.googlesource.com/967056
Reviewed-by: Karan Bhatia <karandeepb@chromium.org>
Commit-Queue: Karan Bhatia <karandeepb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#543921}
[modify] https://crrev.com/7a8a322ad719a0503ba7e8452fad79b6b79cbd04/chrome/browser/chrome_content_browser_client.cc
[modify] https://crrev.com/7a8a322ad719a0503ba7e8452fad79b6b79cbd04/chrome/browser/net/profile_network_context_service.cc
[modify] https://crrev.com/7a8a322ad719a0503ba7e8452fad79b6b79cbd04/chrome/browser/net/profile_network_context_service.h
[modify] https://crrev.com/7a8a322ad719a0503ba7e8452fad79b6b79cbd04/testing/buildbot/filters/mojo.fyi.network_browser_tests.filter