[CRD iOS] Collecting in-session data for telemetry and feedback

This CL makes the iOS app track these fields for telemetry:
* Connection type
* Previous session state

It also makes ChromotingSession export a FeedbackData from current
telemetry data, to be attached to the feedback report.

Bug: 814863
Change-Id: Iab32eb5da6748a0e3b7f6d251fa2d7c926c01392
Reviewed-on: https://chromium-review.googlesource.com/939102
Commit-Queue: Yuwei Huang <[email protected]>
Reviewed-by: Jamie Walch <[email protected]>
Cr-Commit-Position: refs/heads/master@{#539635}
9 files changed