Finish autofill integration with keyboard cleanup tasks

1. Only print log when debug is on.
2. Callback be notified when input does not start.
3. Avoid using hard code tag in Log class.
4. onCreateInlineSuggestionsRequest() do nothing in NOP.
5. Add missing javadoc.

Bug: 146525448
Test: manual verification
Change-Id: I41e1de92ffcdb8020aef99acbfec274e0294bad3