Separates PreviousSessionInfo testing interface

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")
 import("//third_party/protobuf/proto_library.gni")
 
 declare_args() {
   google_test_gaia_client_id = ""
@@ skipping 225 matching lines @@
     "metrics/ios_chrome_metrics_services_manager_client.h",
     "metrics/ios_chrome_metrics_services_manager_client.mm",
     "metrics/ios_chrome_origins_seen_service_factory.cc",
     "metrics/ios_chrome_origins_seen_service_factory.h",
     "metrics/ios_chrome_stability_metrics_provider.cc",
     "metrics/ios_chrome_stability_metrics_provider.h",
     "metrics/mobile_session_shutdown_metrics_provider.h",
     "metrics/mobile_session_shutdown_metrics_provider.mm",
     "metrics/previous_session_info.h",
     "metrics/previous_session_info.mm",
+    "metrics/previous_session_info_private.h",
     "net/chrome_cookie_store_ios_client.h",
     "net/chrome_cookie_store_ios_client.mm",
     "net/connection_type_observer_bridge.h",
     "net/connection_type_observer_bridge.mm",
     "net/cookie_util.h",
     "net/cookie_util.mm",
     "net/crl_set_fetcher.cc",
     "net/crl_set_fetcher.h",
     "net/http_server_properties_manager_factory.cc",
     "net/http_server_properties_manager_factory.h",
@@ skipping 504 matching lines @@
     "//ios/public/provider/chrome/browser",
     "//ios/public/provider/chrome/browser:test_support",
     "//ios/web",
     "//sync",
     "//testing/gmock",
     "//testing/gtest",
     "//ui/base",
     "//url",
   ]
 }