Revert "Notification to warn user of excessive displays (Low level code)"

This reverts commit 0d3c39fb10fc3f1392313dce1f12c4d7338923d3.

Reason for revert: The bug in the previous CL causes crash when connected with multiple
drmDevices. So revert and then reland with the updated version.

Original change's description:
> Notification to warn user of excessive displays (Low level code)
>
> Split the original CL as code reviewer requests. Code in this CL is
> responsible for: when a new display is connected with device, check
> whether the device is able to support the incoming display connection.
> The result of the check is included in DisplaySnapshot as boolean value.
> For more details, please see doc link under the issue page.
>
> Introduction of the original CL:
> User may connect more external displays than the number of crtc that
> the device can provide. On some latest chromebooks, like the Pixel book,
> when this happens, one of connected external displays (randomly chosen)
> gets disconnected. However there is no notification for this. And this CL
> tries to fix this problem.
>
> Change-Id: I9c464d339d85e2dc09476c072700e265965b311e
> Bug: 827406
> Reviewed-on: https://chromium-review.googlesource.com/c/1373138
> Commit-Queue: Andrew Xu <andrewxu@chromium.org>
> Reviewed-by: Daniele Castagna <dcastagna@chromium.org>
> Reviewed-by: Mitsuru Oshima (OOO til 3/4) <oshima@chromium.org>
> Reviewed-by: Mustafa Emre Acer <meacer@chromium.org>
> Reviewed-by: Robert Kroeger <rjkroege@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#637025}

TBR=rjkroege@chromium.org,marcheu@chromium.org,oshima@chromium.org,meacer@chromium.org,dcastagna@chromium.org,andrewxu@chromium.org

Bug: 827406
Change-Id: I96b4ce82f7bfd3695c7e39f110cb0cc352e39ee9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1526893
Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Commit-Queue: Mitsuru Oshima <oshima@chromium.org>
Cr-Commit-Position: refs/heads/master@{#641517}
27 files changed