Adds custom ttl argument to HostCache::Set.

net/dns/async_host_resolver.cc

Index: net/dns/async_host_resolver.cc
diff --git a/net/dns/async_host_resolver.cc b/net/dns/async_host_resolver.cc
index 6f6552bcfa684a7c680c9076ef19733c45e9918c..81133fbae03d541799a0b0cd8aa2176d199b750f 100644
--- a/net/dns/async_host_resolver.cc
+++ b/net/dns/async_host_resolver.cc
@@ -349,8 +349,9 @@ void AsyncHostResolver::OnDnsRequestComplete(
   RequestList& requests = rit->second;
   int port = requests.empty() ? 80 : requests.front()->info().port();
 
-  // Extract AddressList out of DnsResponse.
+  // Extract AddressList and TTL out of DnsResponse.
   AddressList addr_list;
+  uint32 ttl = kuint32max;
   if (result == OK) {
     IPAddressList ip_addresses;
     DnsRecordParser parser = response->Parser();
@@ -362,6 +363,7 @@ void AsyncHostResolver::OnDnsRequestComplete(
            record.rdata.size() == kIPv6AddressSize)) {
         ip_addresses.push_back(IPAddressNumber(record.rdata.begin(),
                                                record.rdata.end()));
+        ttl = std::min(ttl, record.ttl);

[cbentzel, 2012/01/20 11:04:53]

I thought all of the RR's in the RRSet need to have identical TTL's. Did you
decide to be permissive here? Is this consistent with other resolvers?

[szym, 2012/01/20 16:31:46]

This policy is just a stub. We really should check that the A/AAAA-RRs that we
are collecting match the QNAME or a CNAME alias. The TTL should then be the
min(CNAME.TTL, A.TTL).

I'm planning to write this policy and tests for it in HostResolverImpl.

       }
     }
     if (!ip_addresses.empty())
@@ -389,7 +391,11 @@ void AsyncHostResolver::OnDnsRequestComplete(
     HostResolver::RequestInfo info = request->info();
     HostCache::Key key(
         info.hostname(), info.address_family(), info.host_resolver_flags());
-    cache_->Set(key, result, addr_list, base::TimeTicks::Now());
+    cache_->Set(key,
+                result,
+                addr_list,
+                base::TimeTicks::Now(),
+                base::TimeDelta::FromSeconds(ttl));
   }
 
   // Cleanup requests.