Revert "Reland "Reland "[Media Feeds] Add feed items to WebUI"""

This reverts commit 0b8fa0e522d6a4c27048142306b11e1a1f6ad79e.

Reason for revert: Causing failures on Win7:
https://ci.chromium.org/p/chromium/builders/ci/Win7%20%2832%29%20Tests

2020-03-28 11:06 AM (JST) 80527764939c8e498dec513eef0f3a4d1d478579	FAILURE	58352	1 Test Suite(s) failed. browser_tests failed because of:
MediaFeedsWebUIBrowserTest.All

Original change's description:
> Reland "Reland "[Media Feeds] Add feed items to WebUI""
> 
> This is a reland of 25e377304652f41edf16f0a7163891949853e129
> 
> The fix is to loosen the assertion on the time fields
> which have a different format on win7.
> 
> Original change's description:
> > Reland "[Media Feeds] Add feed items to WebUI"
> >
> > This is a reland of 0bbf0f94329faaf15dc188c7b6facda7c7d047ce
> >
> > Original change's description:
> > > [Media Feeds] Add feed items to WebUI
> > >
> > > This adds the feed items to the WebUI. You
> > > can select a feed to show the content.
> > >
> > > BUG=1058187
> > >
> > > Change-Id: I5051f77b68cb3da6710a547d50109cb95a7b890f
> > > Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2118758
> > > Commit-Queue: Becca Hughes <beccahughes@chromium.org>
> > > Reviewed-by: Tommy Steimel <steimel@chromium.org>
> > > Cr-Commit-Position: refs/heads/master@{#753441}
> >
> > Bug: 1058187
> > Change-Id: I7ec8a25ba03d192341e6d02eccfba991b4156504
> > Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2121450
> > Reviewed-by: Tommy Steimel <steimel@chromium.org>
> > Commit-Queue: Becca Hughes <beccahughes@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#753712}
> 
> Bug: 1058187
> Change-Id: I69f0f6dbe336d7a46b2c3d2e4e251256d37390d5
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2124630
> Reviewed-by: Tommy Steimel <steimel@chromium.org>
> Commit-Queue: Becca Hughes <beccahughes@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#754202}

TBR=beccahughes@chromium.org,steimel@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 1058187
Change-Id: I48de21fbe3659c80de0c76aebc69f4f818fa24f6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2126327
Reviewed-by: Johann Koenig <johannkoenig@google.com>
Commit-Queue: Johann Koenig <johannkoenig@google.com>
Cr-Commit-Position: refs/heads/master@{#754378}