[CrOS Tether]: Add LocalDeviceDataProvider, which fetches device data for the local device.

components/cryptauth/cryptauth_enrollment_manager.cc

 // 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.
 
 #include "components/cryptauth/cryptauth_enrollment_manager.h"
 
 #include <utility>
 
 #include "base/base64url.h"
 #include "base/memory/ptr_util.h"
@@ skipping 149 matching lines @@
 }
 
 std::unique_ptr<SyncScheduler>
 CryptAuthEnrollmentManager::CreateSyncScheduler() {
   return base::MakeUnique<SyncSchedulerImpl>(
       this, base::TimeDelta::FromDays(kEnrollmentRefreshPeriodDays),
       base::TimeDelta::FromMinutes(kEnrollmentBaseRecoveryPeriodMinutes),
       kEnrollmentMaxJitterRatio, "CryptAuth Enrollment");
 }
 
-std::string CryptAuthEnrollmentManager::GetUserPublicKey() {
+std::string CryptAuthEnrollmentManager::GetUserPublicKey() const {
   std::string public_key;
   if (!base::Base64UrlDecode(
           pref_service_->GetString(prefs::kCryptAuthEnrollmentUserPublicKey),
           base::Base64UrlDecodePolicy::REQUIRE_PADDING, &public_key)) {
     PA_LOG(ERROR) << "Invalid public key stored in user prefs.";
     return std::string();
   }
   return public_key;
 }
 
-std::string CryptAuthEnrollmentManager::GetUserPrivateKey() {
+std::string CryptAuthEnrollmentManager::GetUserPrivateKey() const {
   std::string private_key;
   if (!base::Base64UrlDecode(
           pref_service_->GetString(prefs::kCryptAuthEnrollmentUserPrivateKey),
           base::Base64UrlDecodePolicy::REQUIRE_PADDING, &private_key)) {
     PA_LOG(ERROR) << "Invalid private key stored in user prefs.";
     return std::string();
   }
   return private_key;
 }
 
@@ skipping 103 matching lines @@
                << device_info.gcm_registration_id();
 
   cryptauth_enroller_ = enroller_factory_->CreateInstance();
   cryptauth_enroller_->Enroll(
       GetUserPublicKey(), GetUserPrivateKey(), device_info, invocation_reason,
       base::Bind(&CryptAuthEnrollmentManager::OnEnrollmentFinished,
                  weak_ptr_factory_.GetWeakPtr()));
 }
 
 }  // namespace cryptauth