Map MathML elements to specific roles

This CL introduces the minimal number of MathML roles so that one can
implement role and attribute mapping for ATK and AX API [1]. Exact
roles for some tags are still being discussed on the spec side and
might change in the future [2] [3] [4] [5] [6]. On Windows and Android
platforms, math roles is a bit undefined and so some dummy role mapping
is used right now. Node tests are added to cover all elements of MathML
Core. These new tests also verify that the MathML element tags are
exposed as an AtkObject attribute.

[1] https://w3c.github.io/mathml-aam/
[2] w3c/mathml-aam#9
[3] w3c/mathml-aam#11
[4] w3c/mathml-aam#12
[5] w3c/mathml-aam#13
[6] w3c/mathml-aam#14

AX-Relnotes: MathML elements are exposed in the accessible tree with specific roles.
Bug: 6606, 1038895, 1051115, 1038897, 1038898, 1038899, 1038900, 1038901, 1038911, 1038913, 1052420
Change-Id: I7e857a0cfc05616a30bf4842e334c1dfde082d49
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3207929
Commit-Queue: Frédéric Wang <[email protected]>
Reviewed-by: Nektarios Paisios <[email protected]>
Reviewed-by: Tom Sepez <[email protected]>
Cr-Commit-Position: refs/heads/main@{#933442}
NOKEYCHECK=True
GitOrigin-RevId: d6d648b6dc54c1c78936dc506e5ccebe23cee7a3

blink/renderer/core/mathml/mathml_tag_names.json5

@@ -107,6 +107,14 @@
       name: "mtable",
       interfaceName: "MathMLElement",
     },
+    {
+      name: "mtd",
+      interfaceName: "MathMLElement",
+    },
+    {
+      name: "mtr",
+      interfaceName: "MathMLElement",
+    },
     {
       name: "mtext",
       interfaceName: "MathMLElement",

blink/renderer/modules/accessibility/ax_layout_object.cc

@@ -81,6 +81,7 @@
 #include "third_party/blink/renderer/core/layout/ng/inline/ng_inline_node.h"
 #include "third_party/blink/renderer/core/layout/ng/list/layout_ng_list_item.h"
 #include "third_party/blink/renderer/core/loader/progress_tracker.h"
+#include "third_party/blink/renderer/core/mathml/mathml_element.h"
 #include "third_party/blink/renderer/core/page/page.h"
 #include "third_party/blink/renderer/core/paint/paint_layer.h"
 #include "third_party/blink/renderer/core/paint/paint_layer_scrollable_area.h"

blink/renderer/modules/accessibility/ax_node_object.cc

@@ -577,6 +577,14 @@ AXObjectInclusion AXNodeObject::ShouldIncludeBasedOnSemantics(
       always_included_computed_roles.end())
     return kIncludeObject;
 
+  // Don't ignore MathML nodes by default, since MathML relies on child
+  // positions to determine semantics (e.g. numerator is the first child of a
+  // fraction).
+  if (RuntimeEnabledFeatures::MathMLCoreEnabled() && IsA<MathMLElement>(node) &&
+      RoleValue() != ax::mojom::blink::Role::kNone) {
+    return kIncludeObject;
+  }
+
   // Using the title or accessibility description (so we
   // check if there's some kind of accessible name for the element)
   // to decide an element's visibility is not as definitive as
@@ -1073,9 +1081,60 @@ ax::mojom::blink::Role AXNodeObject::NativeRoleIgnoringAria() const {
                  ? ax::mojom::blink::Role::kMathMLMath
                  : ax::mojom::blink::Role::kMath;
     }
-    // TODO(crbug.com/6606): Map more MathML elements.
+    if (element->HasTagName(mathml_names::kMfracTag))
+      return ax::mojom::blink::Role::kMathMLFraction;
+    if (element->HasTagName(mathml_names::kMiTag))
+      return ax::mojom::blink::Role::kMathMLIdentifier;
+    if (element->HasTagName(mathml_names::kMmultiscriptsTag))
+      return ax::mojom::blink::Role::kMathMLMultiscripts;
+    if (element->HasTagName(mathml_names::kMnTag))
+      return ax::mojom::blink::Role::kMathMLNumber;
+    if (element->HasTagName(mathml_names::kMoTag))
+      return ax::mojom::blink::Role::kMathMLOperator;
+    if (element->HasTagName(mathml_names::kMoverTag))
+      return ax::mojom::blink::Role::kMathMLOver;
+    if (element->HasTagName(mathml_names::kMunderTag))
+      return ax::mojom::blink::Role::kMathMLUnder;
+    if (element->HasTagName(mathml_names::kMunderoverTag))
+      return ax::mojom::blink::Role::kMathMLUnderOver;
+    if (element->HasTagName(mathml_names::kMrootTag))
+      return ax::mojom::blink::Role::kMathMLRoot;
+    if (element->HasTagName(mathml_names::kMrowTag) ||
+        element->HasTagName(mathml_names::kAnnotationXmlTag) ||
+        element->HasTagName(mathml_names::kMactionTag) ||
+        element->HasTagName(mathml_names::kMerrorTag) ||
+        element->HasTagName(mathml_names::kMpaddedTag) ||
+        element->HasTagName(mathml_names::kMphantomTag) ||
+        element->HasTagName(mathml_names::kMstyleTag) ||
+        element->HasTagName(mathml_names::kSemanticsTag)) {
+      return ax::mojom::blink::Role::kMathMLRow;
+    }
+    if (element->HasTagName(mathml_names::kMprescriptsTag))
+      return ax::mojom::blink::Role::kMathMLPrescriptDelimiter;
+    if (element->HasTagName(mathml_names::kNoneTag))
+      return ax::mojom::blink::Role::kMathMLNoneScript;
+    if (element->HasTagName(mathml_names::kMsqrtTag))
+      return ax::mojom::blink::Role::kMathMLSquareRoot;
+    if (element->HasTagName(mathml_names::kMsTag))
+      return ax::mojom::blink::Role::kMathMLStringLiteral;
     if (element->HasTagName(mathml_names::kMspaceTag))
       return ax::mojom::blink::Role::kNone;
+    if (element->HasTagName(mathml_names::kMsubTag))
+      return ax::mojom::blink::Role::kMathMLSub;
+    if (element->HasTagName(mathml_names::kMsubsupTag))
+      return ax::mojom::blink::Role::kMathMLSubSup;
+    if (element->HasTagName(mathml_names::kMsupTag))
+      return ax::mojom::blink::Role::kMathMLSup;
+    if (element->HasTagName(mathml_names::kMtableTag))
+      return ax::mojom::blink::Role::kMathMLTable;
+    if (element->HasTagName(mathml_names::kMtdTag))
+      return ax::mojom::blink::Role::kMathMLTableCell;
+    if (element->HasTagName(mathml_names::kMtrTag))
+      return ax::mojom::blink::Role::kMathMLTableRow;
+    if (element->HasTagName(mathml_names::kMtextTag) ||
+        element->HasTagName(mathml_names::kAnnotationTag)) {
+      return ax::mojom::blink::Role::kMathMLText;
+    }
   }
 
   if (GetNode()->HasTagName(html_names::kRpTag) ||

blink/renderer/modules/accessibility/ax_object.cc

@@ -5640,7 +5640,28 @@ bool AXObject::SupportsNameFromContents(bool recursive) const {
     case ax::mojom::blink::Role::kLog:
     case ax::mojom::blink::Role::kMain:
     case ax::mojom::blink::Role::kMarquee:
+    case ax::mojom::blink::Role::kMathMLFraction:
+    case ax::mojom::blink::Role::kMathMLIdentifier:
     case ax::mojom::blink::Role::kMathMLMath:
+    case ax::mojom::blink::Role::kMathMLMultiscripts:
+    case ax::mojom::blink::Role::kMathMLNoneScript:
+    case ax::mojom::blink::Role::kMathMLNumber:
+    case ax::mojom::blink::Role::kMathMLOperator:
+    case ax::mojom::blink::Role::kMathMLOver:
+    case ax::mojom::blink::Role::kMathMLPrescriptDelimiter:
+    case ax::mojom::blink::Role::kMathMLRoot:
+    case ax::mojom::blink::Role::kMathMLRow:
+    case ax::mojom::blink::Role::kMathMLSquareRoot:
+    case ax::mojom::blink::Role::kMathMLStringLiteral:
+    case ax::mojom::blink::Role::kMathMLSub:
+    case ax::mojom::blink::Role::kMathMLSubSup:
+    case ax::mojom::blink::Role::kMathMLSup:
+    case ax::mojom::blink::Role::kMathMLTable:
+    case ax::mojom::blink::Role::kMathMLTableCell:
+    case ax::mojom::blink::Role::kMathMLTableRow:
+    case ax::mojom::blink::Role::kMathMLText:
+    case ax::mojom::blink::Role::kMathMLUnder:
+    case ax::mojom::blink::Role::kMathMLUnderOver:
     case ax::mojom::blink::Role::kMenuListPopup:
     case ax::mojom::blink::Role::kMenu:
     case ax::mojom::blink::Role::kMenuBar:

blink/web_tests/accessibility/element-role-mapping-normal-expected.txt

@@ -87,40 +87,40 @@ AXRole: AXGenericContainer
         AXRole: AXDescriptionListDetail
             AXRole: AXStaticText "- white cold drink"
                 AXRole: AXInlineTextBox "- white cold drink"
-    AXRole: AXMath "x + a / b"
-        AXRole: AXGenericContainer
-            AXRole: AXGenericContainer
+    AXRole: AXMath
+        AXRole: AXMathMLRow
+            AXRole: AXMathMLIdentifier
                 AXRole: AXStaticText "x"
                     AXRole: AXInlineTextBox "x"
-            AXRole: AXGenericContainer
+            AXRole: AXMathMLOperator
                 AXRole: AXStaticText "+"
                     AXRole: AXInlineTextBox "+"
-            AXRole: AXGenericContainer
-                AXRole: AXGenericContainer
+            AXRole: AXMathMLRow
+                AXRole: AXMathMLIdentifier
                     AXRole: AXStaticText "a"
                         AXRole: AXInlineTextBox "a"
-                AXRole: AXGenericContainer
+                AXRole: AXMathMLOperator
                     AXRole: AXStaticText "/"
                         AXRole: AXInlineTextBox "/"
-                AXRole: AXGenericContainer
+                AXRole: AXMathMLIdentifier
                     AXRole: AXStaticText "b"
                         AXRole: AXInlineTextBox "b"
     AXRole: AXMathMLMath
-        AXRole: AXGenericContainer
-            AXRole: AXGenericContainer
+        AXRole: AXMathMLRow
+            AXRole: AXMathMLIdentifier
                 AXRole: AXStaticText "𝑥"
                     AXRole: AXInlineTextBox "𝑥"
-            AXRole: AXGenericContainer
+            AXRole: AXMathMLOperator
                 AXRole: AXStaticText "+"
                     AXRole: AXInlineTextBox "+"
-            AXRole: AXGenericContainer
-                AXRole: AXGenericContainer
+            AXRole: AXMathMLRow
+                AXRole: AXMathMLIdentifier
                     AXRole: AXStaticText "𝑎"
                         AXRole: AXInlineTextBox "𝑎"
-                AXRole: AXGenericContainer
+                AXRole: AXMathMLOperator
                     AXRole: AXStaticText "/"
                         AXRole: AXInlineTextBox "/"
-                AXRole: AXGenericContainer
+                AXRole: AXMathMLIdentifier
                     AXRole: AXStaticText "𝑏"
                         AXRole: AXInlineTextBox "𝑏"
     AXRole: AXMain

closure_compiler/externs/automation.js

@@ -266,7 +266,28 @@ chrome.automation.RoleType = {
   MARK: 'mark',
   MARQUEE: 'marquee',
   MATH: 'math',
+  MATH_MLFRACTION: 'mathMLFraction',
+  MATH_MLIDENTIFIER: 'mathMLIdentifier',
   MATH_MLMATH: 'mathMLMath',
+  MATH_MLMULTISCRIPTS: 'mathMLMultiscripts',
+  MATH_MLNUMBER: 'mathMLNumber',
+  MATH_MLOPERATOR: 'mathMLOperator',
+  MATH_MLOVER: 'mathMLOver',
+  MATH_MLROOT: 'mathMLRoot',
+  MATH_MLROW: 'mathMLRow',
+  MATH_MLSQUARE_ROOT: 'mathMLSquareRoot',
+  MATH_MLSTRING_LITERAL: 'mathMLStringLiteral',
+  MATH_MLSUB: 'mathMLSub',
+  MATH_MLSUB_SUP: 'mathMLSubSup',
+  MATH_MLSUP: 'mathMLSup',
+  MATH_MLTABLE: 'mathMLTable',
+  MATH_MLTABLE_CELL: 'mathMLTableCell',
+  MATH_MLTABLE_ROW: 'mathMLTableRow',
+  MATH_MLTEXT: 'mathMLText',
+  MATH_MLUNDER: 'mathMLUnder',
+  MATH_MLUNDER_OVER: 'mathMLUnderOver',
+  MATH_MLPRESCRIPT_DELIMITER: 'mathMLPrescriptDelimiter',
+  MATH_MLNONE_SCRIPT: 'mathMLNoneScript',
   MENU: 'menu',
   MENU_BAR: 'menuBar',
   MENU_ITEM: 'menuItem',