Update app open/close animations.

- For app open, the icon text remains where it is and only the icon moves.
- Similarly for app close, the icon text remains where it is and fades in
  with the rest of the other icons text.

- With this change, the original view is always "VISIBLE"
  (if BubbleTextView/FolderIcon) but we hide certain elements.

Added video to bug.

Bug: 137200188
Bug: 139885365
Change-Id: I3d20c5f05bc7c0b9d052d8074ac3bfc21531c83d

src/com/android/launcher3/FastBitmapDrawable.java

@@ -142,8 +142,11 @@ public class FastBitmapDrawable extends Drawable {
 
     @Override
     public void setAlpha(int alpha) {
-        mAlpha = alpha;
-        mPaint.setAlpha(alpha);
+        if (mAlpha != alpha) {
+            mAlpha = alpha;
+            mPaint.setAlpha(alpha);
+            invalidateSelf();
+        }
     }
 
     @Override