Update accessibility compat classes for N.

Adding getTitle and getAnchor to AccessibilityWindowInfoCompat.

Adding getDrawingOrder, setDrawingOrder, isImportantForAccessibility,
and setImportantForAccessibility to AccessibilityNodeInfoCompat.

Updating API and making CompatApi24 classes package private.

Bug: 28912621
Change-Id: I30cf7567abf1535f35b5176b9fe4c644ce4d2d72
5 files changed