AX: Add accessibility tests for MathML operators

[Frédéric Wang (:fredw)]

This is for when bug 99620 is fixed.

I'm not sure I see tests for

AccessibilityRenderObject::isMathOperator()                 (<mo> renderers or the anonymous created by <mfenced>)
AccessibilityRenderObject::isMathFenceOperator()            (fences created by <mfenced>)
AccessibilityRenderObject::isMathSeparatorOperator()        (separators created by <mfenced>)

After bugs 99620 is fixed, we will have the following attributes:

<mo fence="true"> => isMathFenceOperator
<mo separator="true"> => isMathSeparatorOperator
<mo separator="true" fence="true"> => isMathFenceOperator && isMathSeparatorOperator (not sure this really exists in real math)

Also, the values can be determined from the operator dictionary (http://www.w3.org/TR/MathML3/appendixc.html). For example the two markup should be equivalent for the AT:

<math><mo>(</mo><mi>x</mi><mo>,<mo><mi>y</mi><mo>;</mo><mo>]</mo></math>

and with explicit attributes

<math><mo fence="true">(</mo><mi>x</mi><mo separator="true">,<mo><mi>y</mi><mo separator="true">;</mo><mo fence="true">]</mo></math>

Similarly, we should have the equivalence between mfenced and its expanded form. See http://www.w3.org/TR/MathML3/chapter3.html#presm.mfenced

[Frédéric Wang (:fredw)]

There is also the separate questions of whether we want to expose other operator properties to the AT. Most of the new properties are purely visual but perhaps "LargeOp" and "Accent" have a semantic meaning that is worth exposing.

[Radar WebKit Bug Importer]

<rdar://problem/16119302>

[Frédéric Wang (:fredw)]

@Chris: now that bug 99620 is fixed, I let you ensure correct test coverage for the AT and decide whether it is worth exposing things like "LargeOp" or "Accent".

[Frédéric Wang (:fredw)]

For the record: the accessibility test has been disabled in http://trac.webkit.org/changeset/165436 because the change broke the <mfenced> test. We need to be restore it and ensure it works with normal <mo> elements too.

[Frédéric Wang (:fredw)]

Created attachment 282234 [details]
Patch

[Build Bot]

Comment on attachment 282234 [details]
Patch

Attachment 282234 [details] did not pass ios-sim-ews (ios-simulator-wk2):
Output: http://webkit-queues.webkit.org/results/1585623

New failing tests:
animations/multiple-backgrounds.html

[Build Bot]

Created attachment 282240 [details]
Archive of layout-test-results from ews126 for ios-simulator-wk2

The attached test failures were seen while running run-webkit-tests on the ios-sim-ews.
Bot: ews126  Port: ios-simulator-wk2  Platform: Mac OS X 10.11.4

[Frédéric Wang (:fredw)]

Created attachment 282243 [details]
Patch to get test expectations

[Frédéric Wang (:fredw)]

Created attachment 282252 [details]
Patch

Adding the mac expectation...

[Joanmarie Diggs]

Comment on attachment 282252 [details]
Patch

Yay for more tests! :) Thanks!

[Frédéric Wang (:fredw)]

Committed r202610: <http://trac.webkit.org/changeset/202610>