QUIC - Android - small experiment to flush http_server_properties

changes to disk every 500ms instead of 5secs. We are hoping if QUIC is
used as an alternate protocol, we will persist that information to disk
quicker. Hopefully, this would improve the QUIC winning the alternate
protocol race.

R=rch@chromium.org

Review URL: https://codereview.chromium.org/667473003

Cr-Commit-Position: refs/heads/master@{#300318}

net/http/http_server_properties_manager.cc

@@ -27,7 +27,13 @@ const int64 kUpdateCacheDelayMs = 1000;
 // Time to wait before starting an update the preferences from the
 // http_server_properties_impl_ cache. Scheduling another update during this
 // period will reset the timer.
+// TODO(rtenneti): Remove OS_ANDROID ifdef after testing if flushing of
+// AlternateProtocolHosts to disk in 500ms helps with QUIC's 0RTT or not.
+#if defined(OS_ANDROID)
+const int64 kUpdatePrefsDelayMs = 500;
+#else
 const int64 kUpdatePrefsDelayMs = 5000;
+#endif
 
 // "version" 0 indicates, http_server_properties doesn't have "version"
 // property.