Android notification: Add setContentIntent API with metric tracking.

This CL adds setContentIntent(PendingIntentProvider) in
ChromeNotificationBuilder. The old API is marked as deprecated and we
will gradually convert all notification use cases to new API.

Consumer can use this API to track notification body click events.

TBR=holte@chromium.org

Bug: 898269
Change-Id: If5aad3b4a7cf949b2d7fc4e3baf0e2b929931462
Reviewed-on: https://chromium-review.googlesource.com/c/1379223
Commit-Queue: Xing Liu <xingliu@chromium.org>
Reviewed-by: David Trainor <dtrainor@chromium.org>
Cr-Commit-Position: refs/heads/master@{#623412}
10 files changed