Provide Recent Disk Perf via IStoraged

Expose recent disk write performance to Java side services.

Bug: 62393328
Test: manual
Change-Id: I6002681b17e7f5b9538b4dc9e312843cf838e467
diff --git a/storaged/storaged_info.cpp b/storaged/storaged_info.cpp
index 036d7e1..b39804d 100644
--- a/storaged/storaged_info.cpp
+++ b/storaged/storaged_info.cpp
@@ -213,6 +213,13 @@
     return ret;
 }
 
+uint32_t storage_info_t::get_recent_perf() {
+    Mutex::Autolock _l(si_mutex);
+    if (recent_perf.size() == 0) return 0;
+    return accumulate(recent_perf.begin(), recent_perf.end(), recent_perf.size() / 2) /
+           recent_perf.size();
+}
+
 void emmc_info_t::report()
 {
     if (!report_sysfs() && !report_debugfs())