Bug 1520611 - Prune children in Android. r=yzen

Differential Revision: https://phabricator.services.mozilla.com/D16743

--HG--
extra : moz-landing-system : lando

accessible/android/AccessibleWrap.cpp

@@ -581,15 +581,20 @@ mozilla::java::GeckoBundle::LocalRef AccessibleWrap::ToBundle(
     }
   }
 
-  auto childCount = ChildCount();
-  nsTArray<int32_t> children(childCount);
-  for (uint32_t i = 0; i < childCount; i++) {
-    auto child = static_cast<AccessibleWrap*>(GetChildAt(i));
-    children.AppendElement(child->VirtualViewID());
+  bool mustPrune =
+      IsProxy() ? nsAccUtils::MustPrune(Proxy()) : nsAccUtils::MustPrune(this);
+  if (!mustPrune) {
+    auto childCount = ChildCount();
+    nsTArray<int32_t> children(childCount);
+    for (uint32_t i = 0; i < childCount; i++) {
+      auto child = static_cast<AccessibleWrap*>(GetChildAt(i));
+      children.AppendElement(child->VirtualViewID());
+    }
+
+    GECKOBUNDLE_PUT(nodeInfo, "children",
+                    jni::IntArray::New(children.Elements(), children.Length()));
   }
 
-  GECKOBUNDLE_PUT(nodeInfo, "children",
-                  jni::IntArray::New(children.Elements(), children.Length()));
   GECKOBUNDLE_FINISH(nodeInfo);
 
   return nodeInfo;

accessible/base/nsAccUtils.cpp

@@ -399,11 +399,21 @@ bool nsAccUtils::MustPrune(AccessibleOrProxy aAccessible) {
     return true;
   }
 
+#if defined(ANDROID)
+  if (role == roles::LINK) {
+    // Always prune links in Android
+    return true;
+  }
+#endif
+
   if (role != roles::MENUITEM && role != roles::COMBOBOX_OPTION &&
       role != roles::OPTION && role != roles::ENTRY &&
       role != roles::FLAT_EQUATION && role != roles::PASSWORD_TEXT &&
       role != roles::PUSHBUTTON && role != roles::TOGGLE_BUTTON &&
       role != roles::GRAPHIC && role != roles::PROGRESSBAR &&
+#if defined(ANDROID)
+      role != roles::HEADING &&
+#endif
       role != roles::SEPARATOR) {
     // If it doesn't match any of these roles, don't prune its children.
     return false;

mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/AccessibilityTest.kt

@@ -839,12 +839,9 @@ class AccessibilityTest : BaseSessionTest() {
 
         val buttonNode = createNodeInfo(rootNode.getChildId(2))
         assertThat("Last node is a button", buttonNode.className.toString(), equalTo("android.widget.Button"))
-        assertThat("Button has a single text leaf", buttonNode.childCount, equalTo(1))
+        // The child text leaf is pruned, so this button is childless.
+        assertThat("Button has a single text leaf", buttonNode.childCount, equalTo(0))
         assertThat("Button has correct text", buttonNode.text.toString(), equalTo("Submit"))
-
-        val textLeaf = createNodeInfo(buttonNode.getChildId(0))
-        assertThat("First node is a label", textLeaf.className.toString(), equalTo("android.view.View"))
-        assertThat("Text leaf has correct text", textLeaf.text.toString(), equalTo("Submit"))
     }
 
     @Setting(key = Setting.Key.FULL_ACCESSIBILITY_TREE, value = "true")