Following CL does not create intersection observer for the control group when the image is not lazyloadable.
https://chromium-review.googlesource.com/c/chromium/src/+/1372317

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/d5c134ea1b3a533e5ae0a0a2df12f2a9e63711f2

commit d5c134ea1b3a533e5ae0a0a2df12f2a9e63711f2
Author: rajendrant <rajendrant@chromium.org>
Date: Wed Dec 12 10:47:55 2018

LazyLoad: Do not record visibility metrics for undeferrable images

Some images cannot be lazyloaded, for example., images with dimensions in attribute or style,
and images inside iframes which are already lazyloaded. For such images creating intersection
observer and recording visibility metrics is not needed. This also reduces the amout of
intersection observers.

Bug:  914024 
Change-Id: I34907ac9c7930964288544c135a8e3cbe2262f61
Reviewed-on: https://chromium-review.googlesource.com/c/1372317
Commit-Queue: rajendrant <rajendrant@chromium.org>
Reviewed-by: Fredrik Söderquist <fs@opera.com>
Cr-Commit-Position: refs/heads/master@{#615848}
[modify] https://crrev.com/d5c134ea1b3a533e5ae0a0a2df12f2a9e63711f2/third_party/blink/renderer/core/html/lazy_load_image_observer.cc
[modify] https://crrev.com/d5c134ea1b3a533e5ae0a0a2df12f2a9e63711f2/third_party/blink/renderer/core/html/lazy_load_image_observer.h
[modify] https://crrev.com/d5c134ea1b3a533e5ae0a0a2df12f2a9e63711f2/third_party/blink/renderer/core/loader/image_loader.cc

Request to merge c#3 to M72.
This should be a safe CL. This just modifiesthe conditions lazload of images applies to. This would be necessary for some TTFCP regressions we see in dev/canary.

This bug requires manual review: M72 has already been promoted to the beta branch, so this requires manual review
Please contact the milestone owner if you have questions.
Owners: govind@(Android), kariahda@(iOS), djmm@(ChromeOS), abdulsyed@(Desktop)

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

Approving merge for cl listed at #3 to M72 branch 3626 based on comment #4. Please merge ASAP. Thank you.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/917075dab5e685c19cd0cd174ff2367244cebb04

commit 917075dab5e685c19cd0cd174ff2367244cebb04
Author: rajendrant <rajendrant@chromium.org>
Date: Fri Dec 14 20:31:15 2018

LazyLoad: Do not record visibility metrics for undeferrable images

Some images cannot be lazyloaded, for example., images with dimensions in attribute or style,
and images inside iframes which are already lazyloaded. For such images creating intersection
observer and recording visibility metrics is not needed. This also reduces the amout of
intersection observers.

(cherry picked from commit d5c134ea1b3a533e5ae0a0a2df12f2a9e63711f2)

Bug:  914024 
Change-Id: I34907ac9c7930964288544c135a8e3cbe2262f61
Reviewed-on: https://chromium-review.googlesource.com/c/1372317
Commit-Queue: rajendrant <rajendrant@chromium.org>
Reviewed-by: Fredrik Söderquist <fs@opera.com>
Cr-Original-Commit-Position: refs/heads/master@{#615848}
Reviewed-on: https://chromium-review.googlesource.com/c/1378628
Reviewed-by: rajendrant <rajendrant@chromium.org>
Cr-Commit-Position: refs/branch-heads/3626@{#366}
Cr-Branched-From: d897fb137fbaaa9355c0c93124cc048824eb1e65-refs/heads/master@{#612437}
[modify] https://crrev.com/917075dab5e685c19cd0cd174ff2367244cebb04/third_party/blink/renderer/core/html/lazy_load_image_observer.cc
[modify] https://crrev.com/917075dab5e685c19cd0cd174ff2367244cebb04/third_party/blink/renderer/core/html/lazy_load_image_observer.h
[modify] https://crrev.com/917075dab5e685c19cd0cd174ff2367244cebb04/third_party/blink/renderer/core/loader/image_loader.cc

The following revision refers to this bug: 
https://chromium.googlesource.com/chromium/src.git/+/917075dab5e685c19cd0cd174ff2367244cebb04

Commit: 917075dab5e685c19cd0cd174ff2367244cebb04
Author: rajendrant@chromium.org
Commiter: rajendrant@chromium.org
Date: 2018-12-14 20:31:15 +0000 UTC

LazyLoad: Do not record visibility metrics for undeferrable images

Some images cannot be lazyloaded, for example., images with dimensions in attribute or style,
and images inside iframes which are already lazyloaded. For such images creating intersection
observer and recording visibility metrics is not needed. This also reduces the amout of
intersection observers.

(cherry picked from commit d5c134ea1b3a533e5ae0a0a2df12f2a9e63711f2)

Bug:  914024 
Change-Id: I34907ac9c7930964288544c135a8e3cbe2262f61
Reviewed-on: https://chromium-review.googlesource.com/c/1372317
Commit-Queue: rajendrant <rajendrant@chromium.org>
Reviewed-by: Fredrik Söderquist <fs@opera.com>
Cr-Original-Commit-Position: refs/heads/master@{#615848}
Reviewed-on: https://chromium-review.googlesource.com/c/1378628
Reviewed-by: rajendrant <rajendrant@chromium.org>
Cr-Commit-Position: refs/branch-heads/3626@{#366}
Cr-Branched-From: d897fb137fbaaa9355c0c93124cc048824eb1e65-refs/heads/master@{#612437}