Make WidgetsRecyclerView not crash on MNC support lib

Change-Id: Ia7bee39752ad0c0b58e74df4507caaf7a3cd8c29
diff --git a/src/com/android/launcher3/widget/WidgetsRecyclerView.java b/src/com/android/launcher3/widget/WidgetsRecyclerView.java
index 4aa3323..9d265f8 100644
--- a/src/com/android/launcher3/widget/WidgetsRecyclerView.java
+++ b/src/com/android/launcher3/widget/WidgetsRecyclerView.java
@@ -25,7 +25,6 @@
 
 import com.android.launcher3.BaseRecyclerView;
 import com.android.launcher3.Utilities;
-import com.android.launcher3.compat.AlphabeticIndexCompat;
 import com.android.launcher3.model.WidgetsModel;
 import com.android.launcher3.model.PackageItemInfo;
 
@@ -37,7 +36,6 @@
     private static final String TAG = "WidgetsRecyclerView";
     private WidgetsModel mWidgets;
     private Rect mBackgroundPadding = new Rect();
-    private PackageItemInfo mLastPackageItemInfo;
 
     public WidgetsRecyclerView(Context context) {
         this(context, null);
@@ -48,9 +46,15 @@
     }
 
     public WidgetsRecyclerView(Context context, AttributeSet attrs, int defStyleAttr) {
+        // API 21 and below only support 3 parameter ctor.
         super(context, attrs, defStyleAttr);
     }
 
+    public WidgetsRecyclerView(Context context, AttributeSet attrs, int defStyleAttr,
+            int defStyleRes) {
+        this(context, attrs, defStyleAttr);
+    }
+
     @Override
     protected void onFinishInflate() {
         super.onFinishInflate();