Bug 1894165: When there is no explicit ARIA role, expose the computed ARIA role via the AriaRole UIA property. r=morgan

Previously, we didn't expose AriaRole at all if there was no explicit ARIA role (as specified by the role attribute).
However, there are quite a few ARIA roles where the UIA control type and other properties don't expose sufficient semantics alone.
Exposing AriaRole in these cases allows clients to perceive these semantics if they wish.

Differential Revision: https://phabricator.services.mozilla.com/D208973

accessible/tests/browser/windows/uia/browser_generalProps.js

@@ -219,3 +219,103 @@ addUiaTask(
   // The IA2 -> UIA proxy doesn't support ClassName.
   { uiaEnabled: true, uiaDisabled: false }
 );
+
+/**
+ * Test the AriaRole property.
+ */
+addUiaTask(
+  `
+<div id="button" role="button">button</div>
+<div id="main" role="main">main</div>
+<div id="unknown" role="unknown">unknown</div>
+<button id="computedButton">computedButton</button>
+<h1 id="computedHeading">computedHeading</h1>
+<main id="computedMain">computedMain</main>
+<div id="generic">generic</div>
+  `,
+  async function testAriaRole() {
+    await definePyVar("doc", `getDocUia()`);
+    is(
+      await runPython(`findUiaByDomId(doc, "button").CurrentAriaRole`),
+      "button",
+      "button has correct AriaRole"
+    );
+    is(
+      await runPython(`findUiaByDomId(doc, "main").CurrentAriaRole`),
+      "main",
+      "main has correct AriaRole"
+    );
+    is(
+      await runPython(`findUiaByDomId(doc, "unknown").CurrentAriaRole`),
+      "unknown",
+      "unknown has correct AriaRole"
+    );
+    // The IA2 -> UIA proxy doesn't compute ARIA roles.
+    if (gIsUiaEnabled) {
+      is(
+        await runPython(
+          `findUiaByDomId(doc, "computedButton").CurrentAriaRole`
+        ),
+        "button",
+        "computedButton has correct AriaRole"
+      );
+      is(
+        await runPython(`findUiaByDomId(doc, "computedMain").CurrentAriaRole`),
+        "main",
+        "computedMain has correct AriaRole"
+      );
+      is(
+        await runPython(
+          `findUiaByDomId(doc, "computedHeading").CurrentAriaRole`
+        ),
+        "heading",
+        "computedHeading has correct AriaRole"
+      );
+      is(
+        await runPython(`findUiaByDomId(doc, "generic").CurrentAriaRole`),
+        "generic",
+        "generic has correct AriaRole"
+      );
+    }
+  }
+);
+
+/**
+ * Test the LocalizedControlType property. We don't support this ourselves, but
+ * the system provides it based on ControlType and AriaRole.
+ */
+addUiaTask(
+  `
+<button id="button">button</button>
+<h1 id="h1">h1</h1>
+<main id="main">main</main>
+  `,
+  async function testLocalizedControlType() {
+    await definePyVar("doc", `getDocUia()`);
+    is(
+      await runPython(
+        `findUiaByDomId(doc, "button").CurrentLocalizedControlType`
+      ),
+      "button",
+      "button has correct LocalizedControlType"
+    );
+    // The IA2 -> UIA proxy doesn't compute ARIA roles, so it can't compute the
+    // correct LocalizedControlType for these either.
+    if (gIsUiaEnabled) {
+      is(
+        await runPython(
+          `findUiaByDomId(doc, "h1").CurrentLocalizedControlType`
+        ),
+        "heading",
+        "h1 has correct LocalizedControlType"
+      );
+      is(
+        await runPython(
+          `findUiaByDomId(doc, "main").CurrentLocalizedControlType`
+        ),
+        "main",
+        "main has correct LocalizedControlType"
+      );
+    }
+  }
+);

accessible/windows/uia/uiaRawElmProvider.cpp

@@ -471,19 +471,19 @@ uiaRawElmProvider::GetPropertyValue(PROPERTYID aPropertyId,
       break;
     }
 
-    // ARIA Role / shortcut
     case UIA_AriaRolePropertyId: {
-      nsAutoString xmlRoles;
-
-      RefPtr<AccAttributes> attributes = acc->Attributes();
-      attributes->GetAttribute(nsGkAtoms::xmlroles, xmlRoles);
-
-      if (!xmlRoles.IsEmpty()) {
+      nsAutoString role;
+      if (acc->HasARIARole()) {
+        RefPtr<AccAttributes> attributes = acc->Attributes();
+        attributes->GetAttribute(nsGkAtoms::xmlroles, role);
+      } else if (nsStaticAtom* computed = acc->ComputedARIARole()) {
+        computed->ToString(role);
+      }
+      if (!role.IsEmpty()) {
         aPropertyValue->vt = VT_BSTR;
-        aPropertyValue->bstrVal = ::SysAllocString(xmlRoles.get());
+        aPropertyValue->bstrVal = ::SysAllocString(role.get());
         return S_OK;
       }
-
       break;
     }