Implement initial LayoutTransition for Taskbar recents.

The animations mostly match the spec, though the recents indicators scale/fade with icon currently.

The change transitions need to incorporate translateX since that changes based on the number of icons in Taskbar. We need the translateX for pinning update to happen before TaskbarView lays out its children so that the animator computes the correct start and end values.

Flag: com.android.launcher3.taskbar_recents_layout_transition
Bug: 343521765
Test: go/testedequals
Change-Id: I13aa49abf80ddc09fab890f78bde924a8f7f1d6e

quickstep/src/com/android/launcher3/taskbar/TaskbarView.java

@@ -839,6 +839,8 @@ public class TaskbarView extends FrameLayout implements FolderIcon.FolderIconPar
             iconEnd += mAllAppsButtonTranslationOffset;
         }
 
+        mControllerCallbacks.onPreLayoutChildren();
+
         int count = getChildCount();
         for (int i = count; i > 0; i--) {
             View child = getChildAt(i - 1);