Fix sending accessibility events to RN modals

Reviewed By: dmmiller

Differential Revision: D3472359

fbshipit-source-id: c82d8e254cdd0531eb52805a6f00e63cf783fdc8

ReactAndroid/src/main/java/com/facebook/react/views/modal/ReactModalHostView.java

@@ -21,6 +21,7 @@
 import android.view.View;
 import android.view.ViewGroup;
 import android.view.WindowManager;
+import android.view.accessibility.AccessibilityEvent;
 
 import com.facebook.infer.annotation.Assertions;
 import com.facebook.react.R;
@@ -109,6 +110,13 @@ public void addChildrenForAccessibility(ArrayList<View> outChildren) {
     // Those will be handled by the mHostView which lives in the dialog
   }
 
+  @Override
+  public boolean dispatchPopulateAccessibilityEvent(AccessibilityEvent event) {
+    // Explicitly override this to prevent accessibility events being passed down to children
+    // Those will be handled by the mHostView which lives in the dialog
+    return false;
+  }
+
   public void onDropInstance() {
     ((ReactContext) getContext()).removeLifecycleEventListener(this);
     dismiss();