GitLab

This CL enables the most basic functionalities: showing and hiding the
dialog, showing sinks and their statuses (no throbber support yet), and
starting and stopping tab mirroring. The dialog is still behind the
ViewsCastDialog feature flag.

- MRDialogControllerViews instantiates MRViewsUI and CastDialogView
  when a dialog is requested, and destroys them when the dialog is
  closed.
- MRViewsUI sends CastDialogModel to CastDialogView whenever sinks or
  routes are updated. It also sends route requests from CastDialogView
  to MediaRouter.

This CL depends on crrev.com/c/1020231.

Bug: 826091
Change-Id: I14ed4811dd7ccdf0144c64b6f079c06d7fc0aa6e
Reviewed-on: https://chromium-review.googlesource.com/1037907
Commit-Queue: Takumi Fujimoto <takumif@chromium.org>
Reviewed-by: mark a. foltz <mfoltz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#558017}