Bug 493683 part 5: When aria-labell/describedby is set, set HasName/DescriptionDependent on the target subtree. r=eeejay

Differential Revision: https://phabricator.services.mozilla.com/D102680

accessible/generic/DocAccessible.cpp

@@ -16,6 +16,7 @@
 #include "nsEventShell.h"
 #include "nsLayoutUtils.h"
 #include "nsTextEquivUtils.h"
+#include "Pivot.h"
 #include "Role.h"
 #include "RootAccessible.h"
 #include "TreeWalker.h"
@@ -851,15 +852,50 @@ void DocAccessible::AttributeChangedImpl(Accessible* aAccessible,
     return;
   }
 
+  dom::Element* elm = aAccessible->GetContent()->AsElement();
   if (aAttribute == nsGkAtoms::aria_describedby) {
     FireDelayedEvent(nsIAccessibleEvent::EVENT_DESCRIPTION_CHANGE, aAccessible);
+    if (aModType == dom::MutationEvent_Binding::MODIFICATION ||
+        aModType == dom::MutationEvent_Binding::ADDITION) {
+      // The subtrees of the new aria-describedby targets might be used to
+      // compute the description for aAccessible. Therefore, we need to set
+      // the eHasDescriptionDependent flag on all Accessibles in these subtrees.
+      IDRefsIterator iter(this, aAccessible->Elm(),
+                          nsGkAtoms::aria_describedby);
+      while (Accessible* target = iter.Next()) {
+        Pivot pivot(target);
+        LocalAccInSameDocRule rule;
+        for (AccessibleOrProxy anchor(target); !anchor.IsNull();
+             anchor = pivot.Next(anchor, rule)) {
+          Accessible* acc = anchor.AsAccessible();
+          MOZ_ASSERT(acc);
+          acc->mContextFlags |= eHasDescriptionDependent;
+        }
+      }
+    }
     return;
   }
 
-  dom::Element* elm = aAccessible->GetContent()->AsElement();
   if (aAttribute == nsGkAtoms::aria_labelledby &&
       !elm->HasAttr(kNameSpaceID_None, nsGkAtoms::aria_label)) {
     FireDelayedEvent(nsIAccessibleEvent::EVENT_NAME_CHANGE, aAccessible);
+    if (aModType == dom::MutationEvent_Binding::MODIFICATION ||
+        aModType == dom::MutationEvent_Binding::ADDITION) {
+      // The subtrees of the new aria-labelledby targets might be used to
+      // compute the name for aAccessible. Therefore, we need to set
+      // the eHasNameDependent flag on all Accessibles in these subtrees.
+      IDRefsIterator iter(this, aAccessible->Elm(), nsGkAtoms::aria_labelledby);
+      while (Accessible* target = iter.Next()) {
+        Pivot pivot(target);
+        LocalAccInSameDocRule rule;
+        for (AccessibleOrProxy anchor(target); !anchor.IsNull();
+             anchor = pivot.Next(anchor, rule)) {
+          Accessible* acc = anchor.AsAccessible();
+          MOZ_ASSERT(acc);
+          acc->mContextFlags |= eHasNameDependent;
+        }
+      }
+    }
     return;
   }
 

accessible/tests/mochitest/events/test_descrchange.html

@@ -90,6 +90,22 @@
       getNode("descriptionChild").textContent = "d4";
       await descChanged;
 
+      const lateDescribedBy = getNode("lateDescribedBy");
+      descChanged = PromEvents.waitForEvent(
+        EVENT_DESCRIPTION_CHANGE,
+        lateDescribedBy
+      );
+      info("Setting aria-describedby");
+      lateDescribedBy.setAttribute("aria-describedby", "lateDescription");
+      await descChanged;
+      descChanged = PromEvents.waitForEvent(
+        EVENT_DESCRIPTION_CHANGE,
+        lateDescribedBy
+      );
+      info("Changing text of late aria-describedby target's child");
+      getNode("lateDescriptionChild").textContent = "d2";
+      await descChanged;
+
       SimpleTest.finish();
     }
 
@@ -117,6 +133,9 @@
   <div id="describedBy" aria-describedby="description"></div>
   <div id="description">d1</div>
 
+  <div id="lateDescribedBy"></div>
+  <div id="lateDescription"><p id="lateDescriptionChild">d1</p></div>
+
   <div id="eventdump"></div>
 </body>
 </html>

accessible/tests/mochitest/events/test_namechange.html

@@ -119,6 +119,16 @@
       getNode("labelChild").textContent = "l4";
       await nameChanged;
 
+      const lateLabelledBy = getNode("lateLabelledBy");
+      nameChanged = PromEvents.waitForEvent(EVENT_NAME_CHANGE, lateLabelledBy);
+      info("Setting aria-labelledby");
+      lateLabelledBy.setAttribute("aria-labelledby", "lateLabel");
+      await nameChanged;
+      nameChanged = PromEvents.waitForEvent(EVENT_NAME_CHANGE, lateLabelledBy);
+      info("Changing text of late aria-labelledby target's child");
+      getNode("lateLabelChild").textContent = "l2";
+      await nameChanged;
+
       SimpleTest.finish();
     }
 
@@ -148,6 +158,9 @@
   <div id="labelledBy" aria-labelledby="label"></div>
   <div id="label">l1</div>
 
+  <div id="lateLabelledBy"></div>
+  <div id="lateLabel"><p id="lateLabelChild">l1</p></div>
+
   <div id="eventdump"></div>
 </body>
 </html>