Bug 1580000 [wpt PR 18945] - Compute img aspect ratio from width and …

…height HTML attributes, a=testonly

Automatic update from web-platform-tests
Compute img aspect ratio from width and height HTML attributes

As per this intent to implement:
https://groups.google.com/a/chromium.org/forum/?fromgroups#!topic/blink-dev/hbhKRuBzZ4o

Spec:
WICG/intrinsicsize-attribute#16

Bug: 979891
Change-Id: I0f9ffa1584fa12a41393ef05daffb7238c97e990
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1790472
Commit-Queue: Christian Biesinger <cbiesingerchromium.org>
Reviewed-by: Emilio Cobos Álvarez <emiliochromium.org>
Auto-Submit: Christian Biesinger <cbiesingerchromium.org>
Cr-Commit-Position: refs/heads/master{#699465}

--

wpt-commits: 86ff86de45a67eccc781b84f50ab261c18aad5cf
wpt-pr: 18945

UltraBlame original commit: e8962724f6cc584847fedccd8c0912b6bd00dab6

testing/web-platform/tests/html/rendering/replaced-elements/attributes-for-embedded-content-and-images/canvas-aspect-ratio.html

@@ -0,0 +1,253 @@
+<
+!
+doctype
+html
+>
+<
+title
+>
+Canvas
+width
+and
+height
+attributes
+are
+used
+to
+infer
+aspect
+-
+ratio
+<
+/
+title
+>
+<
+script
+src
+=
+"
+/
+resources
+/
+testharness
+.
+js
+"
+>
+<
+/
+script
+>
+<
+script
+src
+=
+"
+/
+resources
+/
+testharnessreport
+.
+js
+"
+>
+<
+/
+script
+>
+<
+style
+>
+canvas
+{
+width
+:
+100
+%
+;
+max
+-
+width
+:
+100px
+;
+height
+:
+auto
+;
+}
+<
+/
+style
+>
+<
+body
+>
+<
+script
+>
+let
+t
+=
+async_test
+(
+"
+Canvas
+width
+and
+height
+attributes
+are
+used
+to
+infer
+aspect
+-
+ratio
+"
+)
+;
+function
+assert_ratio
+(
+img
+expected
+)
+{
+let
+epsilon
+=
+0
+.
+001
+;
+assert_approx_equals
+(
+parseInt
+(
+getComputedStyle
+(
+img
+)
+.
+width
+10
+)
+/
+parseInt
+(
+getComputedStyle
+(
+img
+)
+.
+height
+10
+)
+expected
+epsilon
+)
+;
+}
+/
+/
+Create
+and
+append
+a
+new
+canvas
+and
+immediately
+check
+the
+ratio
+.
+t
+.
+step
+(
+function
+(
+)
+{
+var
+canvas
+=
+document
+.
+createElement
+(
+"
+canvas
+"
+)
+;
+canvas
+.
+setAttribute
+(
+"
+width
+"
+"
+250
+"
+)
+;
+canvas
+.
+setAttribute
+(
+"
+height
+"
+"
+100
+"
+)
+;
+document
+.
+body
+.
+appendChild
+(
+canvas
+)
+;
+/
+/
+Canvases
+always
+use
+the
+aspect
+ratio
+from
+their
+surface
+size
+.
+assert_ratio
+(
+canvas
+2
+.
+5
+)
+;
+t
+.
+done
+(
+)
+;
+}
+)
+;
+<
+/
+script
+>