Remove OS_CHROMEOS from ui/ash code

chrome/browser/ui/ash/chrome_shell_content_state_views.cc

Index: chrome/browser/ui/ash/chrome_shell_content_state_views.cc
diff --git a/chrome/browser/ui/ash/chrome_shell_content_state_views.cc b/chrome/browser/ui/ash/chrome_shell_content_state_views.cc
deleted file mode 100644
index d97db5a6782f9f858ad1114c8a10b5e32fd642d1..0000000000000000000000000000000000000000
--- a/chrome/browser/ui/ash/chrome_shell_content_state_views.cc
+++ /dev/null
@@ -1,21 +0,0 @@
-// Copyright 2015 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "chrome/browser/ui/ash/chrome_shell_content_state.h"
-
-content::BrowserContext* ChromeShellContentState::GetBrowserContextByIndex(
-    ash::UserIndex index) {
-  return nullptr;
-}
-
-content::BrowserContext* ChromeShellContentState::GetBrowserContextForWindow(
-    aura::Window* window) {
-  return nullptr;
-}
-
-content::BrowserContext*
-ChromeShellContentState::GetUserPresentingBrowserContextForWindow(
-    aura::Window* window) {
-  return nullptr;
-}