Whenever NAS called TextClassifier.suggestConversationActions,
it will cache the notification key to result id mapping.
The result id will be used to log subsequent events related to
these suggestions.
This change should allow us to collect CTR.
TODO: Log the coverage, i.e. among all suggestConversationActions
request, how many of them actually contains some suggestions.
BUG: 120803809
Test: atest SmartActionHelperTest
Test: Manual, add a log in TextClassifierImpl.onTextClassifierEvent
1. Send a message notification
2. Expand the notification, observe event is logged.
4. Clicked on one of the replies, observe event is logged.
5. Send another message to myself
6. Inline reply it, observe event is logged.
Change-Id: I590d9bfcdb7ae7ee7976740d71bf7f1204683939
e94e0787db