Some Autofill API changes.

- Added View.IMPORTANT_FOR_AUTOFILL_YES_INCLUDE_DESCENDANTS
- Added View.IMPORTANT_FOR_AUTOFILL_NO_EXCLUDE_DESCENDANTS
- Added FillResponse.Builder.setIgnoredIds()
- Fixed javadoc links.

These changes are not implemented yet....

Bug: 37424141
Bug: 36171235
Test: m update-api

Change-Id: I604960443ab08cd3f2a84a70b0a2cece7cb0a00c