[ios] WebStateList owns all WebState it manages.

ios/chrome/browser/ui/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.
 
 import("//build/config/ios/rules.gni")
 
 source_set("ui") {
   sources = [
     "UIView+SizeClassSupport.h",
     "UIView+SizeClassSupport.mm",
@@ skipping 293 matching lines @@
     "//ios/chrome/browser/ui/util",
     "//ios/chrome/browser/ui/voice",
     "//ios/chrome/browser/upgrade",
     "//ios/chrome/browser/web",
     "//ios/chrome/browser/web:web_internal",
     "//ios/chrome/common",
     "//ios/net",
     "//ios/public/provider/chrome/browser",
     "//ios/public/provider/chrome/browser/ui",
     "//ios/public/provider/chrome/browser/voice",
+    "//ios/shared/chrome/browser/tabs",
     "//ios/third_party/material_components_ios",
     "//ios/web",
     "//ios/web:user_agent",
     "//net",
     "//third_party/google_toolbox_for_mac",
     "//ui/base",
     "//ui/gfx",
     "//url",
   ]
   public_deps = [
@@ skipping 103 matching lines @@
     "//ios/chrome/test/base:perf_test_support",
     "//ios/shared/chrome/browser/tabs",
     "//ios/shared/chrome/browser/tabs:test_support",
     "//ios/web:test_support",
     "//testing/gtest",
     "//third_party/ocmock",
     "//ui/base:test_support",
   ]
   libs = [ "UIKit.framework" ]
 }