bootstat: Refactor init/utils/boot_clock into base/chrono_utils.

Use this for bootstat and init. This replaces the custom uptime parser in
bootstat.

This is a reland of aosp/338325 with a stubbed implementation for Darwin.

This change also has clang_format fixes (automatic).

Bug: 34352037
Test: chrono_utils_test
Change-Id: I72a62a3ca1ccfc0a4ccc6294ff1776c263144686
diff --git a/bootstat/bootstat.cpp b/bootstat/bootstat.cpp
index a4cc5f2..6f25d96 100644
--- a/bootstat/bootstat.cpp
+++ b/bootstat/bootstat.cpp
@@ -21,6 +21,7 @@
 #include <getopt.h>
 #include <unistd.h>
 
+#include <chrono>
 #include <cmath>
 #include <cstddef>
 #include <cstdio>
@@ -30,15 +31,15 @@
 #include <string>
 #include <vector>
 
-#include <android/log.h>
+#include <android-base/chrono_utils.h>
 #include <android-base/logging.h>
 #include <android-base/parseint.h>
 #include <android-base/strings.h>
+#include <android/log.h>
 #include <cutils/properties.h>
 #include <metricslogger/metrics_logger.h>
 
 #include "boot_event_record_store.h"
-#include "uptime_parser.h"
 
 namespace {
 
@@ -255,7 +256,8 @@
   BootEventRecordStore boot_event_store;
   BootEventRecordStore::BootEventRecord record;
 
-  time_t uptime = bootstat::ParseUptime();
+  auto uptime = std::chrono::duration_cast<std::chrono::seconds>(
+      android::base::boot_clock::now().time_since_epoch());
   time_t current_time_utc = time(nullptr);
 
   if (boot_event_store.GetBootEvent("last_boot_time_utc", &record)) {
@@ -282,22 +284,21 @@
     // Log the amount of time elapsed until the device is decrypted, which
     // includes the variable amount of time the user takes to enter the
     // decryption password.
-    boot_event_store.AddBootEventWithValue("boot_decryption_complete", uptime);
+    boot_event_store.AddBootEventWithValue("boot_decryption_complete", uptime.count());
 
     // Subtract the decryption time to normalize the boot cycle timing.
-    time_t boot_complete = uptime - record.second;
+    std::chrono::seconds boot_complete = std::chrono::seconds(uptime.count() - record.second);
     boot_event_store.AddBootEventWithValue(boot_complete_prefix + "_post_decrypt",
-                                           boot_complete);
-
+                                           boot_complete.count());
 
   } else {
-    boot_event_store.AddBootEventWithValue(boot_complete_prefix + "_no_encryption",
-                                           uptime);
+      boot_event_store.AddBootEventWithValue(boot_complete_prefix + "_no_encryption",
+                                             uptime.count());
   }
 
   // Record the total time from device startup to boot complete, regardless of
   // encryption state.
-  boot_event_store.AddBootEventWithValue(boot_complete_prefix, uptime);
+  boot_event_store.AddBootEventWithValue(boot_complete_prefix, uptime.count());
 
   RecordInitBootTimeProp(&boot_event_store, "ro.boottime.init");
   RecordInitBootTimeProp(&boot_event_store, "ro.boottime.init.selinux");