Add histograms and NetLog for host cache persistence

components/cronet/android/cronet_url_request_context_adapter.cc

Index: components/cronet/android/cronet_url_request_context_adapter.cc
diff --git a/components/cronet/android/cronet_url_request_context_adapter.cc b/components/cronet/android/cronet_url_request_context_adapter.cc
index 510ab011c1cc79bf6de577982c37c7c59351a7db..4b94f3144da842841ae8504ff4a28c6de864844b 100644
--- a/components/cronet/android/cronet_url_request_context_adapter.cc
+++ b/components/cronet/android/cronet_url_request_context_adapter.cc
@@ -663,7 +663,11 @@ void CronetURLRequestContextAdapter::InitializeOnNetworkThread(
     if (config->enable_host_cache_persistence) {
       registry->RegisterListPref(kHostCachePref);
     }
-    pref_service_ = factory.Create(registry.get());
+
+    {
+      SCOPED_UMA_HISTOGRAM_TIMER("Net.Cronet.PrefsInitTime");
+      pref_service_ = factory.Create(registry.get());
+    }
 
     // Set up the HttpServerPropertiesManager.
     std::unique_ptr<net::HttpServerPropertiesManager>
@@ -727,7 +731,8 @@ void CronetURLRequestContextAdapter::InitializeOnNetworkThread(
         base::MakeUnique<HostCachePersistenceManager>(
             host_cache, pref_service_.get(), kHostCachePref,
             base::TimeDelta::FromMilliseconds(
-                config->host_cache_persistence_delay_ms));
+                config->host_cache_persistence_delay_ms),
+            g_net_log.Get().net_log());
   }
 
   context_->set_check_cleartext_permitted(true);