This affects animations but is not an animations issue directly, so removing Blink>Animation and cc'ing alancutter as our representative instead.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/9c88a15f059aec65af294b8789a27cc377363da6

commit 9c88a15f059aec65af294b8789a27cc377363da6
Author: rune <rune@opera.com>
Date: Thu Jun 30 08:10:17 2016

Optimize style recalc when adding @keyframes.

We only need to recalculate the elements with running animations unless
we tried to find an @keyframes rule and couldn't, for which we fall
back to a full document recalc.

The motivation for doing this is that the current WIP for  issue 567021 
shows that we're still getting full document recalcs due to the
presence of @keyframes rules.

R=dstockwell@chromium.org,alancutter@chromium.org
BUG= 623911 , 567021 

Review-Url: https://codereview.chromium.org/2105743002
Cr-Commit-Position: refs/heads/master@{#403118}

[add] https://crrev.com/9c88a15f059aec65af294b8789a27cc377363da6/third_party/WebKit/LayoutTests/animations/add-keyframes-recalc.html
[modify] https://crrev.com/9c88a15f059aec65af294b8789a27cc377363da6/third_party/WebKit/Source/core/animation/Animation.cpp
[modify] https://crrev.com/9c88a15f059aec65af294b8789a27cc377363da6/third_party/WebKit/Source/core/animation/Animation.h
[modify] https://crrev.com/9c88a15f059aec65af294b8789a27cc377363da6/third_party/WebKit/Source/core/animation/AnimationTimeline.cpp
[modify] https://crrev.com/9c88a15f059aec65af294b8789a27cc377363da6/third_party/WebKit/Source/core/animation/AnimationTimeline.h
[modify] https://crrev.com/9c88a15f059aec65af294b8789a27cc377363da6/third_party/WebKit/Source/core/animation/css/CSSAnimations.cpp
[modify] https://crrev.com/9c88a15f059aec65af294b8789a27cc377363da6/third_party/WebKit/Source/core/css/invalidation/StyleSheetInvalidationAnalysis.cpp
[modify] https://crrev.com/9c88a15f059aec65af294b8789a27cc377363da6/third_party/WebKit/Source/core/css/invalidation/StyleSheetInvalidationAnalysis.h
[modify] https://crrev.com/9c88a15f059aec65af294b8789a27cc377363da6/third_party/WebKit/Source/core/dom/StyleEngine.cpp
[modify] https://crrev.com/9c88a15f059aec65af294b8789a27cc377363da6/third_party/WebKit/Source/core/dom/StyleEngine.h

rune@: Could you please confirm if this can be verified manually from the TE's end. Please provide any sample file to test and verify this if any verification is needed here.

Thank you!

Recording a timeline in inspector when loading anim.html shows a style recalc with a full tree element count 1s after the load. With the fix, that recalc count is 0.

Deleted: anim.html 575 bytes

anim.html 575 bytes View Download

 Issue 639699  has been merged into this issue.