Set correct accessibility delegate for the overview mode.

b/32004538

Change-Id: Ie68fe418b777784d747b004600ef1c98e96a4791

src/com/android/launcher3/pageindicators/PageIndicatorLineCaret.java

@@ -142,6 +142,11 @@ public class PageIndicatorLineCaret extends PageIndicator {
         mLauncher.setAllAppsButton(mAllAppsHandle);
     }
 
+    @Override
+    public void setAccessibilityDelegate(AccessibilityDelegate delegate) {
+        mAllAppsHandle.setAccessibilityDelegate(delegate);
+    }
+
     @Override
     protected void onDraw(Canvas canvas) {
         if (mTotalScroll == 0 || mNumPagesFloat == 0) {