Fix UI jank issue

In current layout, app bar and directory recycler view are sibling
views. We have added padding on the recycler view to avoid the overlap
between both components before. However, if the padding value is
wrong, the issue will happen.
To solve jank issue, use predraw listener to ensure it get correct
app bar height before UI drew.

Fix: 123353670
Fix: 126716408
Test: manual
Test: atest DocumentsUITests
Change-Id: I60482b2cf207dcd1bcd0a7d06bfb4c296ececa73