All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=794983

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=8d58b9807517021eca1a4a2830e8d324ed362aa76334ea7f288c4b13e6c9e081


Bot(s) for this bug's original alert(s):

chromium-rel-mac-retina
chromium-rel-mac11-air
chromium-rel-mac11-pro
linux-release

📍 Pinpoint job started.
https://pinpoint-dot-chromeperf.appspot.com/job/12a27b3a040000

📍 Found significant differences after each of 3 commits.
https://pinpoint-dot-chromeperf.appspot.com/job/12a27b3a040000

Properly sets default highlight color in Select-to-Speak.
By katydek@google.com · Thu Dec 07 08:45:53 2017
chromium @ 80eddae997875f588e7d71a14a10f7775d74ab54

Separate out the four classes contained in CSSPropertyValueSet.h into four different files
By meade@chromium.org · Thu Dec 07 09:15:34 2017
chromium @ 951544c9d4f42ebae1262e91a03fe660e09146c5

Automated Commit: Committing new LKGM version 10193.0.0 for chromeos.
By chromeos-commit-bot@chromium.org · Thu Dec 07 09:19:05 2017
chromium @ 41e18f1586f07aaa1a86395aea81332f2d4f993d

Understanding performance regressions:
  http://g.co/ChromePerformanceRegressions

"Separate out the four classes contained in CSSPropertyValueSet.h into four different files" seems like the most likely culprit, assigning to meade@

I'm ooo for Christmas. Please revert if this is a problem.

Sent from my phone. Please excuse brevity.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/cedfd986e1aba860a363c54e3367647b0ded5ec2

commit cedfd986e1aba860a363c54e3367647b0ded5ec2
Author: Eric Willigers <ericwilligers@chromium.org>
Date: Mon Dec 18 00:52:27 2017

Revert "Separate out the four classes contained in CSSPropertyValueSet.h into four different files"

This reverts commit 951544c9d4f42ebae1262e91a03fe660e09146c5.

Reason for revert: Suspected performance regression.

Original change's description:
> Separate out the four classes contained in CSSPropertyValueSet.h into four different files
>
> Bug: 752745
> Cq-Include-Trybots: master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
> Change-Id: I43c650c37c33cb92d500e5e82d437f24faf6287a
> Reviewed-on: https://chromium-review.googlesource.com/795515
> Reviewed-by: Kentaro Hara <haraken@chromium.org>
> Reviewed-by: Eric Willigers <ericwilligers@chromium.org>
> Reviewed-by: Bugs Nash <bugsnash@chromium.org>
> Commit-Queue: meade_UTC10 <meade@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#522385}

TBR=ericwilligers@chromium.org,haraken@chromium.org,senorblanco@chromium.org,meade@chromium.org,bugsnash@chromium.org
BUG= 794983 ,752745

Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel;master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
Change-Id: I2a5cd1bde00080ad50c963f09627dcbeab5c6ba8
Reviewed-on: https://chromium-review.googlesource.com/831372
Commit-Queue: Eric Willigers <ericwilligers@chromium.org>
Reviewed-by: Eric Willigers <ericwilligers@chromium.org>
Cr-Commit-Position: refs/heads/master@{#524633}
[modify] https://crrev.com/cedfd986e1aba860a363c54e3367647b0ded5ec2/third_party/WebKit/Source/core/animation/StringKeyframe.h
[modify] https://crrev.com/cedfd986e1aba860a363c54e3367647b0ded5ec2/third_party/WebKit/Source/core/css/BUILD.gn
[modify] https://crrev.com/cedfd986e1aba860a363c54e3367647b0ded5ec2/third_party/WebKit/Source/core/css/CSSCalculationValueTest.cpp
[modify] https://crrev.com/cedfd986e1aba860a363c54e3367647b0ded5ec2/third_party/WebKit/Source/core/css/CSSPropertyValueSet.cpp
[modify] https://crrev.com/cedfd986e1aba860a363c54e3367647b0ded5ec2/third_party/WebKit/Source/core/css/CSSPropertyValueSet.h
[modify] https://crrev.com/cedfd986e1aba860a363c54e3367647b0ded5ec2/third_party/WebKit/Source/core/css/CSSSelectorWatch.cpp
[modify] https://crrev.com/cedfd986e1aba860a363c54e3367647b0ded5ec2/third_party/WebKit/Source/core/css/FontFaceCacheTest.cpp
[delete] https://crrev.com/63d294e5ae654a7d82d3c47368e4149b4b485590/third_party/WebKit/Source/core/css/ImmutableCSSPropertyValueSet.cpp
[delete] https://crrev.com/63d294e5ae654a7d82d3c47368e4149b4b485590/third_party/WebKit/Source/core/css/ImmutableCSSPropertyValueSet.h
[delete] https://crrev.com/63d294e5ae654a7d82d3c47368e4149b4b485590/third_party/WebKit/Source/core/css/MutableCSSPropertyValueSet.cpp
[delete] https://crrev.com/63d294e5ae654a7d82d3c47368e4149b4b485590/third_party/WebKit/Source/core/css/MutableCSSPropertyValueSet.h
[modify] https://crrev.com/cedfd986e1aba860a363c54e3367647b0ded5ec2/third_party/WebKit/Source/core/css/PropertySetCSSStyleDeclaration.cpp
[modify] https://crrev.com/cedfd986e1aba860a363c54e3367647b0ded5ec2/third_party/WebKit/Source/core/css/StyleRule.cpp
[modify] https://crrev.com/cedfd986e1aba860a363c54e3367647b0ded5ec2/third_party/WebKit/Source/core/css/StyleRule.h
[modify] https://crrev.com/cedfd986e1aba860a363c54e3367647b0ded5ec2/third_party/WebKit/Source/core/css/cssom/InlineStylePropertyMap.cpp
[delete] https://crrev.com/63d294e5ae654a7d82d3c47368e4149b4b485590/third_party/WebKit/Source/core/css/parser/CSSLazyPropertyParser.h
[modify] https://crrev.com/cedfd986e1aba860a363c54e3367647b0ded5ec2/third_party/WebKit/Source/core/css/parser/CSSLazyPropertyParserImpl.h
[modify] https://crrev.com/cedfd986e1aba860a363c54e3367647b0ded5ec2/third_party/WebKit/Source/core/css/parser/CSSParser.h
[modify] https://crrev.com/cedfd986e1aba860a363c54e3367647b0ded5ec2/third_party/WebKit/Source/core/css/parser/CSSParserImpl.cpp
[modify] https://crrev.com/cedfd986e1aba860a363c54e3367647b0ded5ec2/third_party/WebKit/Source/core/css/parser/CSSParserImpl.h
[modify] https://crrev.com/cedfd986e1aba860a363c54e3367647b0ded5ec2/third_party/WebKit/Source/core/css/resolver/MatchResultTest.cpp
[modify] https://crrev.com/cedfd986e1aba860a363c54e3367647b0ded5ec2/third_party/WebKit/Source/core/css/resolver/ViewportStyleResolver.cpp
[modify] https://crrev.com/cedfd986e1aba860a363c54e3367647b0ded5ec2/third_party/WebKit/Source/core/dom/Element.cpp
[modify] https://crrev.com/cedfd986e1aba860a363c54e3367647b0ded5ec2/third_party/WebKit/Source/core/dom/ElementData.cpp
[modify] https://crrev.com/cedfd986e1aba860a363c54e3367647b0ded5ec2/third_party/WebKit/Source/core/dom/PresentationAttributeStyle.cpp
[modify] https://crrev.com/cedfd986e1aba860a363c54e3367647b0ded5ec2/third_party/WebKit/Source/core/editing/EditingStyleTest.cpp
[modify] https://crrev.com/cedfd986e1aba860a363c54e3367647b0ded5ec2/third_party/WebKit/Source/core/editing/Editor.cpp
[modify] https://crrev.com/cedfd986e1aba860a363c54e3367647b0ded5ec2/third_party/WebKit/Source/core/editing/commands/ApplyStyleCommand.cpp
[modify] https://crrev.com/cedfd986e1aba860a363c54e3367647b0ded5ec2/third_party/WebKit/Source/core/editing/commands/ApplyStyleCommandTest.cpp
[modify] https://crrev.com/cedfd986e1aba860a363c54e3367647b0ded5ec2/third_party/WebKit/Source/core/editing/commands/EditorCommand.cpp
[modify] https://crrev.com/cedfd986e1aba860a363c54e3367647b0ded5ec2/third_party/WebKit/Source/core/editing/commands/RemoveFormatCommand.cpp
[modify] https://crrev.com/cedfd986e1aba860a363c54e3367647b0ded5ec2/third_party/WebKit/Source/core/editing/commands/ReplaceSelectionCommand.cpp
[modify] https://crrev.com/cedfd986e1aba860a363c54e3367647b0ded5ec2/third_party/WebKit/Source/core/editing/serializers/StyledMarkupAccumulator.cpp
[modify] https://crrev.com/cedfd986e1aba860a363c54e3367647b0ded5ec2/third_party/WebKit/Source/core/editing/serializers/StyledMarkupSerializer.cpp
[modify] https://crrev.com/cedfd986e1aba860a363c54e3367647b0ded5ec2/third_party/WebKit/Source/core/html/HTMLElement.cpp
[modify] https://crrev.com/cedfd986e1aba860a363c54e3367647b0ded5ec2/third_party/WebKit/Source/core/html/HTMLHRElement.cpp
[modify] https://crrev.com/cedfd986e1aba860a363c54e3367647b0ded5ec2/third_party/WebKit/Source/core/html/HTMLPreElement.cpp
[modify] https://crrev.com/cedfd986e1aba860a363c54e3367647b0ded5ec2/third_party/WebKit/Source/core/html/HTMLTableElement.cpp
[modify] https://crrev.com/cedfd986e1aba860a363c54e3367647b0ded5ec2/third_party/WebKit/Source/core/html/HTMLTablePartElement.cpp
[modify] https://crrev.com/cedfd986e1aba860a363c54e3367647b0ded5ec2/third_party/WebKit/Source/core/svg/SVGAnimateElement.cpp
[modify] https://crrev.com/cedfd986e1aba860a363c54e3367647b0ded5ec2/third_party/WebKit/Source/core/svg/SVGElementRareData.cpp
[modify] https://crrev.com/cedfd986e1aba860a363c54e3367647b0ded5ec2/third_party/WebKit/Source/modules/canvas/canvas2d/CanvasRenderingContext2D.cpp

The graph returned briefly to its usual state after the revert.