Revert of Remove support for Alt-Svc/Alternate Protocol Probability

net/http/http_server_properties.cc

Index: net/http/http_server_properties.cc
diff --git a/net/http/http_server_properties.cc b/net/http/http_server_properties.cc
index 850418d0b39ede2a7230405792bb19fb8f732d08..fc6281e43b5b9c11405ab98936e04a1b668d7c36 100644
--- a/net/http/http_server_properties.cc
+++ b/net/http/http_server_properties.cc
@@ -97,10 +97,11 @@
 std::string AlternativeServiceInfo::ToString() const {
   base::Time::Exploded exploded;
   expiration.LocalExplode(&exploded);
-  return base::StringPrintf(
-      "%s, expires %04d-%02d-%02d %02d:%02d:%02d",
-      alternative_service.ToString().c_str(), exploded.year, exploded.month,
-      exploded.day_of_month, exploded.hour, exploded.minute, exploded.second);
+  return base::StringPrintf("%s, p=%f, expires %04d-%02d-%02d %02d:%02d:%02d",
+                            alternative_service.ToString().c_str(), probability,
+                            exploded.year, exploded.month,
+                            exploded.day_of_month, exploded.hour,
+                            exploded.minute, exploded.second);
 }
 
 // static