The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/95e9975e27c78a128c16e1950374fa73a91cd731

commit 95e9975e27c78a128c16e1950374fa73a91cd731
Author: Daichi Hirono <hirono@chromium.org>
Date: Fri Mar 02 01:50:43 2018

ArcAppWindow should cast View to ShellSurfaceBase.

Previously ArcAppWindow casts View to ShellSurface. However for ARC++
it's actually ClientControlledShellSurface.

To make it generic, the change casts View to ShellSurfaceBase which is a
shared base class of ShellSurface and ClientControlledShellSurface.

Bug:  817244 
Test: Manually tested on kevin
Change-Id: I26604522a6e28999032bd7a1bc1a3466f797cbec
Reviewed-on: https://chromium-review.googlesource.com/939884
Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Commit-Queue: Daichi Hirono <hirono@chromium.org>
Cr-Commit-Position: refs/heads/master@{#540408}
[modify] https://crrev.com/95e9975e27c78a128c16e1950374fa73a91cd731/chrome/browser/ui/ash/launcher/arc_app_window.cc