If easy sign-in is set up, allow TPMTokenLoader to start before login

chrome/browser/signin/easy_unlock_service_signin_chromeos.cc

 // Copyright 2014 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.
 
 #include "chrome/browser/signin/easy_unlock_service_signin_chromeos.h"
 
 #include "base/basictypes.h"
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/stl_util.h"
 #include "base/sys_info.h"
 #include "base/thread_task_runner_handle.h"
 #include "base/time/time.h"
 #include "chrome/browser/chromeos/login/easy_unlock/easy_unlock_key_manager.h"
 #include "chrome/browser/chromeos/login/easy_unlock/easy_unlock_metrics.h"
 #include "chrome/browser/chromeos/login/session/user_session_manager.h"
 #include "chromeos/login/auth/user_context.h"
+#include "chromeos/tpm/tpm_token_loader.h"
 
 namespace {
 
 // The maximum allowed backoff interval when waiting for cryptohome to start.
 uint32 kMaxCryptohomeBackoffIntervalMs = 10000u;
 
 // If the data load fails, the initial interval after which the load will be
 // retried. Further intervals will exponentially increas by factor 2.
 uint32 kInitialCryptohomeBackoffIntervalMs = 200u;
 
@@ skipping 282 matching lines @@
   ResetScreenlockState();
   ShowInitialUserState();
 
   if (should_update_app_state) {
     UpdateAppState();
   } else {
     NotifyUserUpdated();
   }
 
   LoadCurrentUserDataIfNeeded();
+
+  // Start loading TPM system token.
+  // The system token will be needed to sign a nonce using TPM private key
+  // during the sign-in protocol.
+  EasyUnlockScreenlockStateHandler::HardlockState hardlock_state;
+  if (GetPersistedHardlockState(&hardlock_state) &&
+      hardlock_state != EasyUnlockScreenlockStateHandler::NO_PAIRING) {
+    chromeos::TPMTokenLoader::Get()->EnsureStarted();
+  }
 }
 
 void EasyUnlockServiceSignin::LoggedInStateChanged() {
   if (!chromeos::LoginState::Get()->IsUserLoggedIn())
     return;
   UnloadApp();
 }
 
 void EasyUnlockServiceSignin::LoadCurrentUserDataIfNeeded() {
   // TODO(xiyuan): Revisit this when adding tests.
@@ skipping 47 matching lines @@
     return NULL;
 
   std::map<std::string, UserData*>::const_iterator it =
       user_data_.find(user_id_);
   if (it == user_data_.end())
     return NULL;
   if (it->second->state != USER_DATA_STATE_LOADED)
     return NULL;
   return it->second;
 }