Bug 1475376: Support aria-valuetext for implicit ARIA roles. r=MarcoZ

For example, <input type="range"> maps to role="slider", so aria-valuetext should be supported.

MozReview-Commit-ID: IYBVTHP3ZLo

--HG--
extra : rebase_source : 906dfacf92d040abf97b46ff67bafbabc5c9a1ea

accessible/generic/Accessible.cpp

@@ -1355,10 +1355,11 @@ void
 Accessible::Value(nsString& aValue) const
 {
   const nsRoleMapEntry* roleMapEntry = ARIARoleMap();
-  if (!roleMapEntry)
-    return;
 
-  if (roleMapEntry->valueRule != eNoValue) {
+  if ((roleMapEntry && roleMapEntry->valueRule != eNoValue) ||
+      // Bug 1475376: aria-valuetext should also be supported for implicit ARIA
+      // roles; e.g. <input type="range">.
+      HasNumericValue()) {
     // aria-valuenow is a number, and aria-valuetext is the optional text
     // equivalent. For the string value, we will try the optional text
     // equivalent first.
@@ -1374,6 +1375,10 @@ Accessible::Value(nsString& aValue) const
     return;
   }
 
+  if (!roleMapEntry) {
+    return;
+  }
+
   // Value of textbox is a textified subtree.
   if (roleMapEntry->Is(nsGkAtoms::textbox)) {
     nsTextEquivUtils::GetTextEquivFromSubtree(this, aValue);

accessible/tests/mochitest/value/test_progress.html

@@ -26,6 +26,7 @@
       testValue("pr_one", "100%", 1, 0, 1, 0);
       testValue("pr_42", "100%", 42, 0, 1, 0);
       testValue("pr_21", "50%", 21, 0, 42, 0);
+      testValue("pr_valuetext", "value", 0, 0, 1, 0);
 
       SimpleTest.finish();
     }
@@ -56,5 +57,7 @@
   <progress id="pr_one" value="1">this will be read by legacy browsers</progress>
   <progress id="pr_42" value="42">this will be read by legacy browsers</progress>
   <progress id="pr_21" value="21" max="42">this will be read by legacy browsers</progress>
+  <!-- aria-valuetext should work due to implicit progressbar role (bug 1475376) -->
+  <progress id="pr_valuetext" aria-valuetext="value">this will be read by legacy browsers</progress>
 </body>
 </html>

accessible/tests/mochitest/value/test_range.html

@@ -25,6 +25,7 @@
       testValue("range_step", "50", 50, 0, 100, 1);
       testValue("range_min42", "71", 71, 42, 100, 1);
       testValue("range_max42", "21", 21, 0, 42, 1);
+      testValue("range_valuetext", "value", 50, 0, 100, 1);
 
       SimpleTest.finish();
     }
@@ -54,5 +55,7 @@
   <input type="range" id="range_step" step="1">
   <input type="range" id="range_min42" min="42">
   <input type="range" id="range_max42" max="42">
+  <!-- aria-valuetext should work due to implicit slider role (bug 1475376) -->
+  <input type="range" id="range_valuetext" aria-valuetext="value">
 </body>
 </html>