Does this need to be R-V-G?

Probably not? But I wasn't sure if we wanted to discuss privacy policy related stuff in public.

I would assume the policy is/was discussed internally and we are just implementing it through this issue.

That's true.

Why is this implementation part of the dialog?

This is equivalent to the welcome banner in the WebUI dialog that contained a checkbox to agree to the Google Privacy Policy.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/ad2aed5ccb030fc2cd6caa8523fa3e19ffa2e668

commit ad2aed5ccb030fc2cd6caa8523fa3e19ffa2e668
Author: Takumi Fujimoto <takumif@chromium.org>
Date: Sat Jun 23 00:37:14 2018

Add strings for cloud services and media remoting dialogs

This CL adds strings used in the new dialogs.

Dialog screenshots (margins aren't final):
https://drive.google.com/open?id=1j5P7OyZognlhF6dXkb1cTAh1hXsSjQ9H
https://drive.google.com/open?id=1MSonPoMLYt0lfLeq9NfP5yoH15EeVZ6c

Bug:  848891 ,  849020 
Change-Id: Id48ed23018b3171d2dc7d6a9e492594487fcf7d5
Reviewed-on: https://chromium-review.googlesource.com/1112659
Reviewed-by: mark a. foltz <mfoltz@chromium.org>
Commit-Queue: Takumi Fujimoto <takumif@chromium.org>
Cr-Commit-Position: refs/heads/master@{#569859}
[modify] https://crrev.com/ad2aed5ccb030fc2cd6caa8523fa3e19ffa2e668/chrome/app/media_router_strings.grdp

Required to launch for policy reasons.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/f98b0db3723c3e0d7f3d7ccc30f2c3f769d010d4

commit f98b0db3723c3e0d7f3d7ccc30f2c3f769d010d4
Author: Takumi Fujimoto <takumif@chromium.org>
Date: Mon Jun 25 21:07:50 2018

Add a dialog for enabling cloud services for Cast

This CL adds a dialog that allows users to enable cloud services in Cast
(Hangouts/Meet, Cast for EDU), and notifies that those services are
governed by the Google Privacy Policy.

The dialog is shown when the user tries to enable cloud services via the
context menu of the Cast toolbar icon ("Enable cloud services") if
the user has not previously acknowledged this dialog or the first run
flow of the old WebUI dialog.

If the user clicks on the "Enable" button in the dialog, we enable the
preferences kMediaRouterEnableCloudServices and
kMediaRouterCloudServicesPrefSet. If the dialog is closed in another
way, we make no pref changes.

Screenshot:
https://drive.google.com/open?id=1MSonPoMLYt0lfLeq9NfP5yoH15EeVZ6c

Bug:  848891 

Change-Id: I9f565e328ea0fbc84131eef5e0fa3cb179284886
Reviewed-on: https://chromium-review.googlesource.com/1096403
Commit-Queue: Takumi Fujimoto <takumif@chromium.org>
Reviewed-by: Bret Sepulveda <bsep@chromium.org>
Reviewed-by: mark a. foltz <mfoltz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#570179}
[modify] https://crrev.com/f98b0db3723c3e0d7f3d7ccc30f2c3f769d010d4/chrome/browser/ui/BUILD.gn
[add] https://crrev.com/f98b0db3723c3e0d7f3d7ccc30f2c3f769d010d4/chrome/browser/ui/media_router/cloud_services_dialog.cc
[add] https://crrev.com/f98b0db3723c3e0d7f3d7ccc30f2c3f769d010d4/chrome/browser/ui/media_router/cloud_services_dialog.h
[modify] https://crrev.com/f98b0db3723c3e0d7f3d7ccc30f2c3f769d010d4/chrome/browser/ui/toolbar/media_router_contextual_menu.cc
[modify] https://crrev.com/f98b0db3723c3e0d7f3d7ccc30f2c3f769d010d4/chrome/browser/ui/toolbar/media_router_contextual_menu.h
[modify] https://crrev.com/f98b0db3723c3e0d7f3d7ccc30f2c3f769d010d4/chrome/browser/ui/toolbar/media_router_contextual_menu_unittest.cc
[add] https://crrev.com/f98b0db3723c3e0d7f3d7ccc30f2c3f769d010d4/chrome/browser/ui/views/media_router/cloud_services_dialog_view.cc
[add] https://crrev.com/f98b0db3723c3e0d7f3d7ccc30f2c3f769d010d4/chrome/browser/ui/views/media_router/cloud_services_dialog_view.h
[add] https://crrev.com/f98b0db3723c3e0d7f3d7ccc30f2c3f769d010d4/chrome/browser/ui/views/media_router/cloud_services_dialog_view_unittest.cc
[modify] https://crrev.com/f98b0db3723c3e0d7f3d7ccc30f2c3f769d010d4/chrome/common/url_constants.cc
[modify] https://crrev.com/f98b0db3723c3e0d7f3d7ccc30f2c3f769d010d4/chrome/common/url_constants.h
[modify] https://crrev.com/f98b0db3723c3e0d7f3d7ccc30f2c3f769d010d4/chrome/test/BUILD.gn