[ios] Add session saving support to clean skeleton.

ios/shared/chrome/browser/ui/browser_list/browser_list_session_service_factory.mm

Index: ios/shared/chrome/browser/ui/browser_list/browser_list_session_service_factory.mm
diff --git a/ios/shared/chrome/browser/ui/browser_list/browser_list_session_service_factory.mm b/ios/shared/chrome/browser/ui/browser_list/browser_list_session_service_factory.mm
new file mode 100644
index 0000000000000000000000000000000000000000..f97f03bbfe532ca398a070a990af99b0941fb4a5
--- /dev/null
+++ b/ios/shared/chrome/browser/ui/browser_list/browser_list_session_service_factory.mm
@@ -0,0 +1,89 @@
+// Copyright 2017 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 "ios/shared/chrome/browser/ui/browser_list/browser_list_session_service_factory.h"
+
+#include <memory>
+
+#include "base/bind.h"
+#include "base/files/file_path.h"
+#include "base/logging.h"
+#include "base/memory/ptr_util.h"
+#include "base/memory/singleton.h"
+#include "base/strings/sys_string_conversions.h"
+#include "components/keyed_service/ios/browser_state_dependency_manager.h"
+#include "ios/chrome/browser/browser_state/browser_state_otr_helper.h"
+#include "ios/chrome/browser/browser_state/chrome_browser_state.h"
+#import "ios/chrome/browser/sessions/session_service_ios.h"
+#import "ios/shared/chrome/browser/ui/browser_list/browser_list.h"
+#import "ios/shared/chrome/browser/ui/browser_list/browser_list_session_service_impl.h"
+#import "ios/web/public/certificate_policy_cache.h"
+#import "ios/web/public/web_state/session_certificate_policy_cache.h"
+
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
+namespace {
+// WebState factory for BrowserListSessionServiceImpl. The factory is called
+// to create a WebState from serialised session state, so the browser state
+// certificate policy cache is updated with the information from the WebState.
+std::unique_ptr<web::WebState> CreateWebState(
+    ios::ChromeBrowserState* browser_state,
+    CRWSessionStorage* session_storage) {
+  std::unique_ptr<web::WebState> web_state =
+      web::WebState::CreateWithStorageSession(
+          web::WebState::CreateParams(browser_state), session_storage);
+  web_state->GetSessionCertificatePolicyCache()->UpdateCertificatePolicyCache(
+      web::BrowserState::GetCertificatePolicyCache(browser_state));
+  return web_state;
+}
+}
+
+// static
+BrowserListSessionService* BrowserListSessionServiceFactory::GetForBrowserState(
+    ios::ChromeBrowserState* browser_state) {
+  return static_cast<BrowserListSessionService*>(
+      GetInstance()->GetServiceForBrowserState(browser_state, true));
+}
+
+// static
+BrowserListSessionServiceFactory*
+BrowserListSessionServiceFactory::GetInstance() {
+  return base::Singleton<BrowserListSessionServiceFactory>::get();
+}
+
+BrowserListSessionServiceFactory::BrowserListSessionServiceFactory()
+    : BrowserStateKeyedServiceFactory(
+          "BrowserListSessionService",
+          BrowserStateDependencyManager::GetInstance()) {}
+
+BrowserListSessionServiceFactory::~BrowserListSessionServiceFactory() {}
+
+std::unique_ptr<KeyedService>
+BrowserListSessionServiceFactory::BuildServiceInstanceFor(
+    web::BrowserState* context) const {
+  ios::ChromeBrowserState* browser_state =
+      ios::ChromeBrowserState::FromBrowserState(context);
+  // It is safe to use base::Unretained here as BrowserListSessionServiceImpl
+  // will be destroyed before the ChromeBrowserState (as it is a KeyedService).
+  return base::MakeUnique<BrowserListSessionServiceImpl>(
+      BrowserList::FromBrowserState(browser_state),
+      base::SysUTF8ToNSString(browser_state->GetStatePath().AsUTF8Unsafe()),
+      [SessionServiceIOS sharedService],
+      base::BindRepeating(&CreateWebState, base::Unretained(browser_state)));
+}
+
+web::BrowserState* BrowserListSessionServiceFactory::GetBrowserStateToUse(
+    web::BrowserState* context) const {
+  // The off-the-record ChromeBrowserState has its own BrowserListSessionService
+  // to implement restoring the sessions after the application has been evicted
+  // while in the background.
+  return GetBrowserStateOwnInstanceInIncognito(context);
+}
+
+bool BrowserListSessionServiceFactory::ServiceIsNULLWhileTesting() const {
+  // Avoid automatically saving session during unit tests.
+  return true;
+}