Refactor RTL wallpaper code to use getLayoutTransitionOffsetForPage

Bug: 11157913
diff --git a/src/com/android/launcher3/PagedView.java b/src/com/android/launcher3/PagedView.java
index e982985..e724063 100644
--- a/src/com/android/launcher3/PagedView.java
+++ b/src/com/android/launcher3/PagedView.java
@@ -268,8 +268,6 @@
 
     protected final Rect mInsets = new Rect();
 
-    protected int mFirstChildLeft;
-
     public interface PageSwitchListener {
         void onPageSwitch(View newPage, int newPageIndex);
     }
@@ -899,10 +897,6 @@
         requestLayout();
     }
 
-    protected int getFirstChildLeft() {
-        return mFirstChildLeft;
-    }
-
     @Override
     protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
         if (!mIsDataReady || getChildCount() == 0) {
@@ -928,7 +922,7 @@
 
         int verticalPadding = getPaddingTop() + getPaddingBottom();
 
-        int childLeft = mFirstChildLeft = offsetX + (screenWidth - getChildWidth(startIndex)) / 2;
+        int childLeft = offsetX + (screenWidth - getChildWidth(startIndex)) / 2;
         if (mPageScrolls == null || getChildCount() != mChildCountOnLastLayout) {
             mPageScrolls = new int[getChildCount()];
         }