Fixes for floating search bar (e.g. background protection).

- Adds background protection for the search bar
 - Views animating based on keyboard now support manual swipes.

Bug: 213954333
Bug: 259004115
Bug: 251460671
Test: Manual
Change-Id: I055766126fb46a8e8b48907e442c9e54aaa4badf

src/com/android/launcher3/allapps/FloatingHeaderView.java

@@ -364,6 +364,10 @@ public class FloatingHeaderView extends LinearLayout implements
         onHeightUpdated();
     }
 
+    public int getClipTop() {
+        return mHeaderClip.top;
+    }
+
     public void reset(boolean animate) {
         if (mAnimator.isStarted()) {
             mAnimator.cancel();