The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/3027bb105137b6c1c519b9d48ddb802089f33999

commit 3027bb105137b6c1c519b9d48ddb802089f33999
Author: Takumi Fujimoto <takumif@chromium.org>
Date: Tue Jul 18 17:14:27 2017

[Media Router] Limit dialog height to 5 sink list items

This CL limits the height of the sink list view in the Media Router dialog to 5
items (including the search box).

This CL also adds margin-bottom to #sink-list-view instead of dynamically
adding padding-bottom to various elements.

Screenshots:
https://docs.google.com/document/d/12e2KFrz_sltuGsI6VcB_0W7FdgQD8_Z3j3xQXHXOiTU/edit

Bug:  738580 
Change-Id: Ie97e4d04faec148ceb9a2870cbcebce494738f78
Reviewed-on: https://chromium-review.googlesource.com/574972
Commit-Queue: Takumi Fujimoto <takumif@chromium.org>
Reviewed-by: Jennifer Apacible <apacible@chromium.org>
Cr-Commit-Position: refs/heads/master@{#487509}
[modify] https://crrev.com/3027bb105137b6c1c519b9d48ddb802089f33999/chrome/browser/resources/media_router/elements/media_router_container/media_router_container.css
[modify] https://crrev.com/3027bb105137b6c1c519b9d48ddb802089f33999/chrome/browser/resources/media_router/elements/media_router_container/media_router_container.js

This was the subject of a long debate, following implementations that went both ways, when we implemented MR to begin with (though I don't have a reference to this).

I'd like to make sure that a passing comment in a review of an unrelated feature doesn't reverse this behavior unintentionally.

As a user with many devices, I find this behavior to be strictly worse than the old one.  It's a jarring change from old behavior (where you naturally assume the device has not been discovered), and even once you get used to it, if your most commonly used device is below the fold, it requires extra interactions every single time you cast.  I'm unclear why any user with >5 devices would find this to be beneficial.  Can we revisit?