Move metric reporting config to flags

This will enable us to enable periodic reporting according
to the properties set in the device config.

As part of this CL, enable cmdline only flags for thing that
do not make sense to read from system properties.

Test: gtest
Bug: 170149255

Change-Id: I99bae25d89cf3a17906b4d3c671e5c63e9a3c180
diff --git a/runtime/runtime.cc b/runtime/runtime.cc
index d54ef6b..f038969 100644
--- a/runtime/runtime.cc
+++ b/runtime/runtime.cc
@@ -1847,7 +1847,7 @@
   // Class-roots are setup, we can now finish initializing the JniIdManager.
   GetJniIdManager()->Init(self);
 
-  InitMetrics(runtime_options);
+  InitMetrics();
 
   // Runtime initialization is largely done now.
   // We load plugins first since that can modify the runtime state slightly.
@@ -1947,8 +1947,8 @@
   return true;
 }
 
-void Runtime::InitMetrics(const RuntimeArgumentMap& runtime_options) {
-  auto metrics_config = metrics::ReportingConfig::FromRuntimeArguments(runtime_options);
+void Runtime::InitMetrics() {
+  auto metrics_config = metrics::ReportingConfig::FromFlags();
   metrics_reporter_ = metrics::MetricsReporter::Create(metrics_config, this);
 }