The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/713811db8cfa4723dd18ee54db8d4f0a6840d231

commit 713811db8cfa4723dd18ee54db8d4f0a6840d231
Author: rajendrant <rajendrant@chromium.org>
Date: Wed Sep 19 23:20:41 2018

LazyLoad: Implement support for "lazyload" attribute on images

This CL implements support for the "lazyload" attribute on images,
according to https://github.com/whatwg/html/pull/3752, and as part of
the LazyLoad feature. The accepted values are:

"off", which causes the browser to avoid lazily loading the <img> element

"on" and "auto", activate the default behavior of lazily load the <img> element

When the attribute is changed to "off", the deferred image loads immediately.

Bug:  875080 
Change-Id: I839926a9827d019f23aafc40f8315476fe1b3048
Reviewed-on: https://chromium-review.googlesource.com/1197782
Reviewed-by: Hiroshige Hayashizaki <hiroshige@chromium.org>
Reviewed-by: Takashi Toyoshima <toyoshim@chromium.org>
Commit-Queue: rajendrant <rajendrant@chromium.org>
Cr-Commit-Position: refs/heads/master@{#592599}
[modify] https://crrev.com/713811db8cfa4723dd18ee54db8d4f0a6840d231/third_party/WebKit/LayoutTests/NeverFixTests
[modify] https://crrev.com/713811db8cfa4723dd18ee54db8d4f0a6840d231/third_party/WebKit/LayoutTests/TestExpectations
[add] https://crrev.com/713811db8cfa4723dd18ee54db8d4f0a6840d231/third_party/WebKit/LayoutTests/http/tests/lazyload/attribute.html
[modify] https://crrev.com/713811db8cfa4723dd18ee54db8d4f0a6840d231/third_party/blink/renderer/core/html/html_image_element.cc
[modify] https://crrev.com/713811db8cfa4723dd18ee54db8d4f0a6840d231/third_party/blink/renderer/core/html/parser/html_preload_scanner.cc
[modify] https://crrev.com/713811db8cfa4723dd18ee54db8d4f0a6840d231/third_party/blink/renderer/core/html/parser/preload_request.cc
[modify] https://crrev.com/713811db8cfa4723dd18ee54db8d4f0a6840d231/third_party/blink/renderer/core/html/parser/preload_request.h
[modify] https://crrev.com/713811db8cfa4723dd18ee54db8d4f0a6840d231/third_party/blink/renderer/core/loader/document_loader.cc
[modify] https://crrev.com/713811db8cfa4723dd18ee54db8d4f0a6840d231/third_party/blink/renderer/core/loader/image_loader.cc