[ios] Refactor SessionServiceIOS to remove dependency on BrowserState.

ios/chrome/browser/crash_report/crash_restore_helper.mm

 // Copyright 2012 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/chrome/browser/crash_report/crash_restore_helper.h"
 
 #include <memory>
 #include <utility>
 
 #include "base/metrics/histogram_macros.h"
@@ skipping 183 matching lines @@
   DCHECK([tabModel currentTab]);
   infobars::InfoBarManager* infoBarManager =
       [[tabModel currentTab] infoBarManager];
   _tabModel.reset([tabModel retain]);
   SessionCrashedInfoBarDelegate::Create(infoBarManager, self);
   _infoBarBridge.reset(new InfoBarManagerObserverBridge(infoBarManager, self));
 }
 
 - (BOOL)deleteSessionForBrowserState:(ios::ChromeBrowserState*)browserState
                           backupFile:(NSString*)file {
-  SessionServiceIOS* sessionService = [SessionServiceIOS sharedService];
   NSString* stashPath =
       base::SysUTF8ToNSString(browserState->GetStatePath().value());
-  NSString* sessionPath =
-      [sessionService sessionFilePathForDirectory:stashPath];
+  NSString* sessionPath = [SessionServiceIOS sessionPathForDirectory:stashPath];
   NSFileManager* fileManager = [NSFileManager defaultManager];
   if (![fileManager fileExistsAtPath:sessionPath])
     return NO;
   if (file) {
     NSError* error = nil;
     BOOL fileOperationSuccess =
         [fileManager removeItemAtPath:file error:&error];
     NSInteger errorCode = fileOperationSuccess ? 0 : [error code];
     UMA_HISTOGRAM_SPARSE_SLOWLY("TabRestore.error_remove_backup_at_path",
                                 errorCode);
@@ skipping 36 matching lines @@
   _needRestoration =
       [self deleteSessionForBrowserState:_browserState
                               backupFile:[self sessionBackupPath]];
 }
 
 - (BOOL)restoreSessionsAfterCrash {
   DCHECK(!_sessionRestored);
   _sessionRestored = YES;
   _infoBarBridge.reset();
   SessionWindowIOS* sessionWindow = [[SessionServiceIOS sharedService]
-      loadWindowFromPath:[self sessionBackupPath]];
+      loadSessionWindowFromPath:[self sessionBackupPath]];
   if (sessionWindow) {
     breakpad_helper::WillStartCrashRestoration();
     return [_tabModel restoreSessionWindow:sessionWindow];
   }
   return NO;
 }
 
 - (void)infoBarRemoved:(infobars::InfoBar*)infobar {
   DCHECK(infobar->delegate());
   if (_sessionRestored ||
       infobar->delegate()->GetIdentifier() !=
           infobars::InfoBarDelegate::SESSION_CRASHED_INFOBAR_DELEGATE) {
     return;
   }
 
   // If the infobar is dismissed without restoring the tabs (either by closing
   // it with the cross or after a navigation), all the entries will be added to
   // the recently closed tabs.
   _sessionRestored = YES;
 
   SessionWindowIOS* window = [[SessionServiceIOS sharedService]
-      loadWindowFromPath:[self sessionBackupPath]];
+      loadSessionWindowFromPath:[self sessionBackupPath]];
   DCHECK(window);
   NSArray* sessions = window.sessions;
   if (!sessions.count)
     return;
   sessions::TabRestoreService* const tabRestoreService =
       IOSChromeTabRestoreServiceFactory::GetForBrowserState(_browserState);
   tabRestoreService->LoadTabsFromLastSession();
 
   web::WebState::CreateParams params(_browserState);
   for (CRWSessionStorage* session in sessions) {
     std::unique_ptr<web::WebState> webState =
         web::WebState::CreateWithStorageSession(params, session);
     // Add all tabs at the 0 position as the position is relative to an old
     // tabModel.
     tabRestoreService->CreateHistoricalTab(
         sessions::IOSLiveTab::GetForWebState(webState.get()), 0);
   }
   return;
 }
 
 @end