Add new ExpandableNotificationRowController.

This reverts commit 372729e8.

The original commit was fine, but the commit it was built upon had
an issue that needed to be fixed. Checking them both back in now.

Bug: 147245740
Test: atest SystemUITests
Change-Id: I94de0f1feec4d2f11e66a2c38b94e4f874503585