update_engine: Use std::optional instead of base::Optional

std::optional is more of standard C++.

BUG=b:171829801
TEST=cros_workon_make --board reef --test update_engine

Change-Id: Id3c5c63634182b975a5da1c3732c7e525b11821a
Reviewed-on: https://chromium-review.googlesource.com/c/aosp/platform/system/update_engine/+/2806373
Commit-Queue: Amin Hassani <[email protected]>
Tested-by: Amin Hassani <[email protected]>
Reviewed-by: Jae Hoon Kim <[email protected]>
diff --git a/cros/download_action_chromeos_unittest.cc b/cros/download_action_chromeos_unittest.cc
index fb78744..ccc122f 100644
--- a/cros/download_action_chromeos_unittest.cc
+++ b/cros/download_action_chromeos_unittest.cc
@@ -754,7 +754,6 @@
   size_t offset = 0;
   for (auto& payload : install_plan.payloads) {
     string file_id = utils::CalculateP2PFileId(payload.hash, payload.size);
-    LOG(INFO) << "test" << file_id;
     EXPECT_EQ(payload.size, p2p_manager_->FileGetSize(file_id));
     string file_content;
     EXPECT_TRUE(
diff --git a/cros/omaha_parser_data.h b/cros/omaha_parser_data.h
index 1677871..0544fbe 100644
--- a/cros/omaha_parser_data.h
+++ b/cros/omaha_parser_data.h
@@ -19,8 +19,7 @@
 
 #include <string>
 #include <vector>
-
-#include <base/optional.h>
+#include <optional>
 
 namespace chromeos_update_engine {
 
@@ -85,9 +84,9 @@
 
   struct App {
     std::string id;
-    base::Optional<std::string> cohort;
-    base::Optional<std::string> cohorthint;
-    base::Optional<std::string> cohortname;
+    std::optional<std::string> cohort;
+    std::optional<std::string> cohorthint;
+    std::optional<std::string> cohortname;
 
     struct Url {
       std::string codebase;
@@ -127,7 +126,7 @@
       std::string disable_hash_checks;
       std::string disable_repeated_updates;
     };
-    base::Optional<PostInstallAction> postinstall_action;
+    std::optional<PostInstallAction> postinstall_action;
 
     struct Package {
       std::string name;
diff --git a/cros/omaha_request_action.cc b/cros/omaha_request_action.cc
index 6afe7ef..73587b5 100644
--- a/cros/omaha_request_action.cc
+++ b/cros/omaha_request_action.cc
@@ -27,7 +27,6 @@
 #include <base/files/file_util.h>
 #include <base/logging.h>
 #include <base/notreached.h>
-#include <base/optional.h>
 #include <base/rand_util.h>
 #include <base/strings/string_number_conversions.h>
 #include <base/strings/stringprintf.h>
@@ -56,7 +55,6 @@
 #include "update_engine/cros/update_attempter.h"
 #include "update_engine/metrics_utils.h"
 
-using base::Optional;
 using base::Time;
 using base::TimeDelta;
 using chromeos_update_manager::kRollforwardInfinity;
@@ -1098,8 +1096,8 @@
   return true;
 }
 
-void OmahaRequestAction::PersistCohortData(const string& prefs_key,
-                                           const Optional<string>& new_value) {
+void OmahaRequestAction::PersistCohortData(
+    const string& prefs_key, const std::optional<string>& new_value) {
   if (!new_value)
     return;
   const string& value = new_value.value();
diff --git a/cros/omaha_request_action.h b/cros/omaha_request_action.h
index 64c02ae..3cd47a8 100644
--- a/cros/omaha_request_action.h
+++ b/cros/omaha_request_action.h
@@ -23,12 +23,12 @@
 
 #include <map>
 #include <memory>
+#include <optional>
 #include <string>
 #include <vector>
 
 #include <gtest/gtest_prod.h>  // for FRIEND_TEST
 
-#include <base/optional.h>
 #include <brillo/secure_blob.h>
 #include <curl/curl.h>
 
@@ -180,7 +180,7 @@
   // deleted. Don't call this function with an empty |new_value| if the value
   // was not set in the XML, since that would delete the stored value.
   void PersistCohortData(const std::string& prefs_key,
-                         const base::Optional<std::string>& new_value);
+                         const std::optional<std::string>& new_value);
 
   // Parses and persists the cohorts sent back in the updatecheck tag
   // attributes.
diff --git a/update_manager/update_time_restrictions_monitor_unittest.cc b/update_manager/update_time_restrictions_monitor_unittest.cc
index 2e474e2..f7adb71 100644
--- a/update_manager/update_time_restrictions_monitor_unittest.cc
+++ b/update_manager/update_time_restrictions_monitor_unittest.cc
@@ -15,8 +15,8 @@
 //
 
 #include <memory>
+#include <optional>
 
-#include <base/optional.h>
 #include <base/time/time.h>
 #include <base/test/simple_test_clock.h>
 #include <brillo/message_loops/fake_message_loop.h>
@@ -144,7 +144,7 @@
   FakeMessageLoop fake_loop_{&test_clock_};
   FakeState fake_state_;
   MockUpdateTimeRestrictionsMonitorDelegate mock_delegate_;
-  base::Optional<UpdateTimeRestrictionsMonitor> monitor_;
+  std::optional<UpdateTimeRestrictionsMonitor> monitor_;
 };
 
 TEST_F(UmUpdateTimeRestrictionsMonitorTest, PolicyIsNotSet) {