The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/bf8eb5c3d6db58b0b46ebd2311b082eb5d4a0119

commit bf8eb5c3d6db58b0b46ebd2311b082eb5d4a0119
Author: Eric Willigers <ericwilligers@chromium.org>
Date: Thu Jan 11 01:31:49 2018

CSS Basic Shapes: Use counters for ellipse

The ellipse shape spec used by clip-path, shape-outside, offset-path
accepts <shape-radius>{2}?, i.e. zero or two <shape-radius> values.
https://drafts.csswg.org/css-shapes-1/#funcdef-ellipse

However, Blink also accepts a single <shape-radius> for clip-path and
shape-outside. Safari similarly accepts a single <shape-radius> for
shape-outside.

CSS WG issue
https://github.com/w3c/csswg-drafts/issues/2175

We add use counters for ellipse with different numbes of <shape-radius> values.

BUG= 800307 

Change-Id: I8f05eecc4b04d860ee690dda2f55478329d23cbf
Reviewed-on: https://chromium-review.googlesource.com/860965
Reviewed-by: nainar <nainar@chromium.org>
Commit-Queue: Eric Willigers <ericwilligers@chromium.org>
Cr-Commit-Position: refs/heads/master@{#528521}
[modify] https://crrev.com/bf8eb5c3d6db58b0b46ebd2311b082eb5d4a0119/third_party/WebKit/Source/core/css/parser/CSSPropertyParserTest.cpp
[modify] https://crrev.com/bf8eb5c3d6db58b0b46ebd2311b082eb5d4a0119/third_party/WebKit/Source/core/css/properties/CSSParsingUtils.cpp
[modify] https://crrev.com/bf8eb5c3d6db58b0b46ebd2311b082eb5d4a0119/third_party/WebKit/public/platform/web_feature.mojom
[modify] https://crrev.com/bf8eb5c3d6db58b0b46ebd2311b082eb5d4a0119/tools/metrics/histograms/enums.xml