Don't overwrite accessibility delegates in AbsListView items.

Bug: 6856579
Change-Id: I2963edcefdc0dd5e1413b57858e6f319904a269d

Author: alanv

core/java/android/view/View.java

@@ -4924,6 +4924,18 @@ && isShown()
         return false;
     }
 
+    /**
+     * Returns the delegate for implementing accessibility support via
+     * composition. For more details see {@link AccessibilityDelegate}.
+     *
+     * @return The delegate, or null if none set.
+     *
+     * @hide
+     */
+    public AccessibilityDelegate getAccessibilityDelegate() {
+        return mAccessibilityDelegate;
+    }
+
     /**
      * Sets a delegate for implementing accessibility support via compositon as
      * opposed to inheritance. The delegate's primary use is for implementing

core/java/android/widget/AbsListView.java

@@ -2158,7 +2158,9 @@ View obtainView(int position, boolean[] isScrap) {
             if (mAccessibilityDelegate == null) {
                 mAccessibilityDelegate = new ListItemAccessibilityDelegate();
             }
-            child.setAccessibilityDelegate(mAccessibilityDelegate);
+            if (child.getAccessibilityDelegate() == null) {
+                child.setAccessibilityDelegate(mAccessibilityDelegate);
+            }
         }
 
         return child;