am ad44d814: am 3dc08220: am b57f236e: Merge changes Icf7d67e2,Ia914ec88,I2490ad75,Ie79f2d28 into mnc-dev
* commit 'ad44d814':
Add a hidden method to clear NetworkCapabilities.
Fix javadoc error for requestNetwork.
Simplify network callback handling code.
Document and unhide CALLBACK_PRECHECK.