Revert of Enable iPad Tab Switcher by default on iOS.

ios/chrome/browser/BUILD.gn

 # 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.
 
 import("//build/config/features.gni")
 import("//ios/web/js_compile.gni")
 
 declare_args() {
   google_test_gaia_client_id = ""
   google_test_gaia_client_secret = ""
@@ skipping 341 matching lines @@
     "signin/signin_error_controller_factory.h",
     "signin/signin_manager_factory.cc",
     "signin/signin_manager_factory.h",
     "signin/signin_manager_factory_observer.h",
     "signin/signin_util.h",
     "signin/signin_util.mm",
     "snapshots/lru_cache.h",
     "snapshots/lru_cache.mm",
     "snapshots/snapshot_cache.h",
     "snapshots/snapshot_cache.mm",
-    "snapshots/snapshot_cache_internal.h",
     "snapshots/snapshot_manager.h",
     "snapshots/snapshot_manager.mm",
     "snapshots/snapshot_overlay.h",
     "snapshots/snapshot_overlay.mm",
     "snapshots/snapshots_util.h",
     "snapshots/snapshots_util.mm",
     "ssl/ios_chrome_security_state_model_client.h",
     "ssl/ios_chrome_security_state_model_client.mm",
     "ssl/ios_ssl_blocking_page.h",
     "ssl/ios_ssl_blocking_page.mm",
@@ skipping 369 matching lines @@
     "//ios/public/provider/chrome/browser",
     "//ios/public/provider/chrome/browser:test_support",
     "//ios/web",
     "//sync",
     "//testing/gmock",
     "//testing/gtest",
     "//ui/base",
     "//url",
   ]
 }