[ios] Use WebStateList to back the tab grid.

ios/clean/chrome/browser/ui/tab_grid/BUILD.gn

 # Copyright 2016 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.
 
 source_set("tab_grid") {
   sources = [
     "tab_grid_coordinator.h",
     "tab_grid_coordinator.mm",
   ]
 
   configs += [ "//build/config/compiler:enable_arc" ]
 
   deps = [
     ":tab_grid_ui",
     "//base",
     "//ios/chrome/browser/browser_state",
     "//ios/clean/chrome/browser",
     "//ios/clean/chrome/browser/model",
     "//ios/clean/chrome/browser/ui/commands",
     "//ios/clean/chrome/browser/ui/settings",
     "//ios/clean/chrome/browser/ui/tab",
     "//ios/shared/chrome/browser/coordinator_context",
+    "//ios/shared/chrome/browser/tabs",
     "//ios/web",
     "//net",
     "//ui/base",
   ]
 }
 
 source_set("tab_grid_ui") {
   sources = [
     "mdc_floating_button+cr_tab_grid.h",
     "mdc_floating_button+cr_tab_grid.mm",
@@ skipping 17 matching lines @@
     "//ios/chrome/browser/ui",
     "//ios/chrome/browser/ui/colors",
     "//ios/chrome/browser/ui/tab_switcher",
     "//ios/clean/chrome/browser/ui/actions",
     "//ios/clean/chrome/browser/ui/animators",
     "//ios/clean/chrome/browser/ui/commands",
     "//ios/third_party/material_components_ios:material_components_ios",
     "//ui/base",
   ]
 }