Allow AllApps to restore current selected tab on activity recreate

This CL also fixes:

- Wrong tab selection on RTL
- Fixes header protection hydraulic scroll issue
- Work toggle button text background contrast

Bug: 186005219
Bug: 191250799
Bug: 191227662
Bug: 191349226
Test: Manual
Change-Id: I3777474c954ed0d542ac38ff552367904be147d3

src/com/android/launcher3/views/SpringRelativeLayout.java

@@ -108,8 +108,6 @@ public class SpringRelativeLayout extends RelativeLayout {
             switch (direction) {
                 case DIRECTION_TOP:
                     return new EdgeEffectProxy(getContext(), mEdgeGlowTop);
-                case DIRECTION_BOTTOM:
-                    return new EdgeEffectProxy(getContext(), mEdgeGlowBottom);
             }
             return super.createEdgeEffect(view, direction);
         }