The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/b5278c3633150f6030882dc717426f690ffadeca

commit b5278c3633150f6030882dc717426f690ffadeca
Author: Scott Little <sclittle@chromium.org>
Date: Thu Aug 16 22:01:48 2018

LazyLoad: Implement support for "lazyload" attribute on frames.

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

"on", which causes the browser to lazily load a frame even if it's
same-origin or nested inside another lazyloaded frame,

"off", which causes the browser to avoid lazily loading this frame or
any of it's children (unless those children are marked with
lazyload="on"),

"auto", which activates the default behavior, and is therefore not
explicitly handled in code.

Bug:  873358 
Change-Id: I2fde65adb15216260291b08e39888a2363f44d4a
Reviewed-on: https://chromium-review.googlesource.com/1176293
Commit-Queue: Scott Little <sclittle@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Cr-Commit-Position: refs/heads/master@{#583841}
[modify] https://crrev.com/b5278c3633150f6030882dc717426f690ffadeca/third_party/blink/renderer/core/html/html_attribute_names.json5
[modify] https://crrev.com/b5278c3633150f6030882dc717426f690ffadeca/third_party/blink/renderer/core/html/html_frame_owner_element.cc
[modify] https://crrev.com/b5278c3633150f6030882dc717426f690ffadeca/third_party/blink/renderer/core/html/html_frame_owner_element.h
[modify] https://crrev.com/b5278c3633150f6030882dc717426f690ffadeca/third_party/blink/renderer/core/html/lazy_load_frame_observer.cc
[modify] https://crrev.com/b5278c3633150f6030882dc717426f690ffadeca/third_party/blink/renderer/core/html/lazy_load_frame_observer.h
[modify] https://crrev.com/b5278c3633150f6030882dc717426f690ffadeca/third_party/blink/renderer/core/html/lazy_load_frame_observer_test.cc