Make CloudPolicyValidator memory management clearer

chrome/browser/chromeos/policy/device_cloud_policy_store_chromeos.cc

Index: chrome/browser/chromeos/policy/device_cloud_policy_store_chromeos.cc
diff --git a/chrome/browser/chromeos/policy/device_cloud_policy_store_chromeos.cc b/chrome/browser/chromeos/policy/device_cloud_policy_store_chromeos.cc
index 882f8e6408e460e7025cd77aab356d9fa6023662..b07010370f8dbf6e89aba37fe805cf34bd42d9e6 100644
--- a/chrome/browser/chromeos/policy/device_cloud_policy_store_chromeos.cc
+++ b/chrome/browser/chromeos/policy/device_cloud_policy_store_chromeos.cc
@@ -71,7 +71,8 @@ void DeviceCloudPolicyStoreChromeOS::Store(
       CloudPolicyValidatorBase::TIMESTAMP_FULLY_VALIDATED,
       CloudPolicyValidatorBase::DM_TOKEN_REQUIRED,
       CloudPolicyValidatorBase::DEVICE_ID_REQUIRED);
-  validator.release()->StartValidation(
+  DeviceCloudPolicyValidator::StartValidation(
+      std::move(validator),
       base::Bind(&DeviceCloudPolicyStoreChromeOS::OnPolicyToStoreValidated,
                  weak_factory_.GetWeakPtr()));
 }
@@ -94,7 +95,8 @@ void DeviceCloudPolicyStoreChromeOS::InstallInitialPolicy(
   std::unique_ptr<DeviceCloudPolicyValidator> validator(
       CreateValidator(policy));
   validator->ValidateInitialKey(install_attributes_->GetDomain());
-  validator.release()->StartValidation(
+  DeviceCloudPolicyValidator::StartValidation(
+      std::move(validator),
       base::Bind(&DeviceCloudPolicyStoreChromeOS::OnPolicyToStoreValidated,
                  weak_factory_.GetWeakPtr()));
 }
@@ -113,8 +115,7 @@ DeviceCloudPolicyStoreChromeOS::CreateValidator(
     const em::PolicyFetchResponse& policy) {
   std::unique_ptr<DeviceCloudPolicyValidator> validator(
       DeviceCloudPolicyValidator::Create(
-          std::unique_ptr<em::PolicyFetchResponse>(
-              new em::PolicyFetchResponse(policy)),
+          base::MakeUnique<em::PolicyFetchResponse>(policy),
           background_task_runner_));
   validator->ValidateDomain(install_attributes_->GetDomain());
   validator->ValidatePolicyType(dm_protocol::kChromeDevicePolicyType);