Reduce statsd binary size from 730KB-> 664KB

1. StatsdStats does not use the proto object in memory anymore.
2. lite_static -> lite
3. don't use sstream

Bug: 72129300
Test: statsd_test

Change-Id: I8a5adaf222d4d5034e8bf115215fb6dd5f042cac
diff --git a/cmds/statsd/src/config/ConfigKey.cpp b/cmds/statsd/src/config/ConfigKey.cpp
index d791f86..4a2bd27 100644
--- a/cmds/statsd/src/config/ConfigKey.cpp
+++ b/cmds/statsd/src/config/ConfigKey.cpp
@@ -16,14 +16,10 @@
 
 #include "config/ConfigKey.h"
 
-#include <sstream>
-
 namespace android {
 namespace os {
 namespace statsd {
 
-using std::ostringstream;
-
 ConfigKey::ConfigKey() {
 }
 
@@ -37,9 +33,9 @@
 }
 
 string ConfigKey::ToString() const {
-    ostringstream out;
-    out << '(' << mUid << ',' << mId << ')';
-    return out.str();
+    string s;
+    s += "(" + std::to_string(mUid) + " " + std::to_string(mId) + ")";
+    return s;
 }