The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/ba39ed57a09afdcf993eff77d70268b8c110be34

commit ba39ed57a09afdcf993eff77d70268b8c110be34
Author: drott <drott@chromium.org>
Date: Mon Dec 12 12:40:10 2016

Add CSS support for font-variation-settings

Implemented analogously to font-feature-settings, as their definition in
the spec is quite similar as well [1].

Add an experimental web platform features flag for CSSVariableFonts.

[1] https://drafts.csswg.org/css-fonts-4/#low-level-font-variation-settings-control-the-font-variation-settings-property

TEST=fast/css/font-variation-settings-css-support.html
BUG= 669455 , 669460 

Review-Url: https://codereview.chromium.org/2558053002
Cr-Commit-Position: refs/heads/master@{#437853}

[add] https://crrev.com/ba39ed57a09afdcf993eff77d70268b8c110be34/third_party/WebKit/LayoutTests/fast/css/font-variation-settings-css-support.html
[add] https://crrev.com/ba39ed57a09afdcf993eff77d70268b8c110be34/third_party/WebKit/LayoutTests/fast/css/resources/font-variation-settings-css-support.js
[modify] https://crrev.com/ba39ed57a09afdcf993eff77d70268b8c110be34/third_party/WebKit/LayoutTests/webexposed/css-properties-as-js-properties-expected.txt
[modify] https://crrev.com/ba39ed57a09afdcf993eff77d70268b8c110be34/third_party/WebKit/Source/core/css/BUILD.gn
[add] https://crrev.com/ba39ed57a09afdcf993eff77d70268b8c110be34/third_party/WebKit/Source/core/css/CSSFontVariationValue.cpp
[add] https://crrev.com/ba39ed57a09afdcf993eff77d70268b8c110be34/third_party/WebKit/Source/core/css/CSSFontVariationValue.h
[modify] https://crrev.com/ba39ed57a09afdcf993eff77d70268b8c110be34/third_party/WebKit/Source/core/css/CSSProperties.in
[modify] https://crrev.com/ba39ed57a09afdcf993eff77d70268b8c110be34/third_party/WebKit/Source/core/css/CSSValue.cpp
[modify] https://crrev.com/ba39ed57a09afdcf993eff77d70268b8c110be34/third_party/WebKit/Source/core/css/CSSValue.h
[modify] https://crrev.com/ba39ed57a09afdcf993eff77d70268b8c110be34/third_party/WebKit/Source/core/css/ComputedStyleCSSValueMapping.cpp
[modify] https://crrev.com/ba39ed57a09afdcf993eff77d70268b8c110be34/third_party/WebKit/Source/core/css/parser/CSSPropertyParser.cpp
[modify] https://crrev.com/ba39ed57a09afdcf993eff77d70268b8c110be34/third_party/WebKit/Source/core/css/resolver/CSSPropertyPriority.h
[modify] https://crrev.com/ba39ed57a09afdcf993eff77d70268b8c110be34/third_party/WebKit/Source/core/css/resolver/FontBuilder.cpp
[modify] https://crrev.com/ba39ed57a09afdcf993eff77d70268b8c110be34/third_party/WebKit/Source/core/css/resolver/FontBuilder.h
[modify] https://crrev.com/ba39ed57a09afdcf993eff77d70268b8c110be34/third_party/WebKit/Source/core/css/resolver/StyleBuilderConverter.cpp
[modify] https://crrev.com/ba39ed57a09afdcf993eff77d70268b8c110be34/third_party/WebKit/Source/core/css/resolver/StyleBuilderConverter.h
[modify] https://crrev.com/ba39ed57a09afdcf993eff77d70268b8c110be34/third_party/WebKit/Source/core/css/resolver/StyleResolver.cpp
[modify] https://crrev.com/ba39ed57a09afdcf993eff77d70268b8c110be34/third_party/WebKit/Source/core/frame/UseCounter.cpp
[modify] https://crrev.com/ba39ed57a09afdcf993eff77d70268b8c110be34/third_party/WebKit/Source/platform/RuntimeEnabledFeatures.in
[modify] https://crrev.com/ba39ed57a09afdcf993eff77d70268b8c110be34/third_party/WebKit/Source/platform/fonts/FontDescription.cpp
[modify] https://crrev.com/ba39ed57a09afdcf993eff77d70268b8c110be34/third_party/WebKit/Source/platform/fonts/FontDescription.h
[modify] https://crrev.com/ba39ed57a09afdcf993eff77d70268b8c110be34/third_party/WebKit/Source/platform/fonts/opentype/FontSettings.h
[modify] https://crrev.com/ba39ed57a09afdcf993eff77d70268b8c110be34/tools/metrics/histograms/histograms.xml