Chromecast: don't try to upload crash immediately.

This has already been the source of compounding issues after a crash and
isn't a great practice anyways.

To make the upload path cleaner, this also moves some internal code for
Cast ATV settings handling upstream.,,
BUG=internal b/21664262

Review URL:

Cr-Commit-Position: refs/heads/master@{#334417}
15 files changed