Findit identified the culprit r623575 as introducing flaky test(s)
summarized in https://findit-for-me.appspot.com/waterfall/flake/flake-culprit?key=ag9zfmZpbmRpdC1mb3ItbWVyQwsSDEZsYWtlQ3VscHJpdCIxY2hyb21pdW0vODg0ZDA1Mjk4MTk4NzUxY2JmMmZjNTI3MTgxYTk4NDA0ZjQ1ODg0Ygw

Please revert the culprit or disable the test(s) asap. If you are the owner,
please fix!

If the culprit above is wrong, please file a bug using this link:
https://bugs.chromium.org/p/chromium/issues/entry?status=Unconfirmed&labels=Pri-1,Test-Findit-Wrong&components=Tools%3ETest%3EFindit%3EFlakiness&summary=%5BFindit%5D%20Flake%20Analyzer%20-%20Wrong%20culprit%20r623575&comment=Link%20to%20Culprit%3A%20https://findit-for-me.appspot.com/waterfall/flake/flake-culprit?key=ag9zfmZpbmRpdC1mb3ItbWVyQwsSDEZsYWtlQ3VscHJpdCIxY2hyb21pdW0vODg0ZDA1Mjk4MTk4NzUxY2JmMmZjNTI3MTgxYTk4NDA0ZjQ1ODg0Ygw

Automatically posted by the findit-for-me app (https://goo.gl/Ot9f7N).

Reverted at r623603.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/473028e8f8b145400e78bcfe003deaf41f41a9bf

commit 473028e8f8b145400e78bcfe003deaf41f41a9bf
Author: Findit <findit-for-me@appspot.gserviceaccount.com>
Date: Fri Jan 18 01:15:47 2019

Revert "Reland "LazyLoad: Fix deferred loading of CSS background images""

This reverts commit 48b03d944e0f1572130fc435884a6410e25d98b0.

Reason for revert:

Findit (https://goo.gl/kROfz5) identified CL at revision 623866 as the
culprit for flakes in the build cycles as shown on:
https://findit-for-me.appspot.com/waterfall/flake/flake-culprit?key=ag9zfmZpbmRpdC1mb3ItbWVyQwsSDEZsYWtlQ3VscHJpdCIxY2hyb21pdW0vNDhiMDNkOTQ0ZTBmMTU3MjEzMGZjNDM1ODg0YTY0MTBlMjVkOThiMAw

Sample Failed Build: https://ci.chromium.org/buildbot/chromium.linux/linux-xenial-rel/6405

Sample Failed Step: browser_tests on Ubuntu-16.04

Sample Flaky Test: LazyLoadBrowserTest.CSSBackgroundImageLoadedWhenScrolled

Original change's description:
> Reland "LazyLoad: Fix deferred loading of CSS background images"
> 
> kDeferImageLoad bit is not set in the FetchParameters when CSS background
> images need to be deferred. This CL fixes that, and also adds browser
> test and unit test.
> 
> Reland of https://chromium-review.googlesource.com/c/1416878 after
> disabling one browser test in windows, chrome OS.
> 
> TBR=japhet@chromium.org,futhark@chromium.org
> 
> Change-Id: I4ac67981b0e1a52797c3e5e7b7c716feaabc23dc
> Reviewed-on: https://chromium-review.googlesource.com/c/1418396
> Reviewed-by: rajendrant <rajendrant@chromium.org>
> Commit-Queue: rajendrant <rajendrant@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#623866}

Change-Id: If9ad789c45bfff7dd3f154941d940fc5a7cd1121
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug:  922872 
Reviewed-on: https://chromium-review.googlesource.com/c/1419016
Cr-Commit-Position: refs/heads/master@{#623936}
[delete] https://crrev.com/f08915e6b745a1ca48ca59de88fd217ab07cbfdc/chrome/browser/previews/lazyload_browsertest.cc
[modify] https://crrev.com/473028e8f8b145400e78bcfe003deaf41f41a9bf/chrome/test/BUILD.gn
[delete] https://crrev.com/f08915e6b745a1ca48ca59de88fd217ab07cbfdc/chrome/test/data/lazyload/css-background-image.html
[delete] https://crrev.com/f08915e6b745a1ca48ca59de88fd217ab07cbfdc/chrome/test/data/lazyload/images/fruit1.jpg
[delete] https://crrev.com/f08915e6b745a1ca48ca59de88fd217ab07cbfdc/chrome/test/data/lazyload/images/fruit2.jpg
[modify] https://crrev.com/473028e8f8b145400e78bcfe003deaf41f41a9bf/third_party/blink/renderer/core/BUILD.gn
[modify] https://crrev.com/473028e8f8b145400e78bcfe003deaf41f41a9bf/third_party/blink/renderer/core/css/css_image_value.cc
[delete] https://crrev.com/f08915e6b745a1ca48ca59de88fd217ab07cbfdc/third_party/blink/renderer/core/html/lazy_load_image_observer_test.cc
[modify] https://crrev.com/473028e8f8b145400e78bcfe003deaf41f41a9bf/third_party/blink/renderer/platform/loader/fetch/fetch_parameters.cc
[modify] https://crrev.com/473028e8f8b145400e78bcfe003deaf41f41a9bf/third_party/blink/renderer/platform/loader/fetch/fetch_parameters.h

Landed the CL without the failing browser test.