Add support for configuring inline update flow.

This CL adds support for controlling the inline update flow from
a feature flag. In addition, it adds support for being able to control
the result of the flow from chrome://flags to enable testing.

BUG=922714

Binary-Size: Adds minimum required functionality for testing inline update flow.
Change-Id: I74e7e58578013848b2e7c297af6ecb8470e65a1b
Reviewed-on: https://chromium-review.googlesource.com/c/1474890
Commit-Queue: Tommy Nyquist <[email protected]>
Reviewed-by: David Trainor <[email protected]>
Cr-Commit-Position: refs/heads/master@{#632868}
15 files changed