Migrate HostReferralList and StartupDNSPrefetchList from local_state to user ...

chrome/browser/net/predictor_api.cc

Index: chrome/browser/net/predictor_api.cc
===================================================================
--- chrome/browser/net/predictor_api.cc	(revision 68772)
+++ chrome/browser/net/predictor_api.cc	(working copy)
@@ -133,12 +133,9 @@
     g_browser_process->io_thread()->ChangedToOnTheRecord();
 }
 
-void RegisterPrefs(PrefService* local_state) {
-  local_state->RegisterListPref(prefs::kDnsStartupPrefetchList);
-  local_state->RegisterListPref(prefs::kDnsHostReferralList);
-}
-
 void RegisterUserPrefs(PrefService* user_prefs) {
+  user_prefs->RegisterListPref(prefs::kDnsStartupPrefetchList);
+  user_prefs->RegisterListPref(prefs::kDnsHostReferralList);
   user_prefs->RegisterBooleanPref(prefs::kDnsPrefetchingEnabled, true);
 }
 
@@ -392,9 +389,13 @@
   UrlList urls =
       GetPredictedUrlListAtStartup(user_prefs, local_state);
 
+  // Migrate HostReferralList from local_state to user prefs if needed.
   ListValue* referral_list =
-      static_cast<ListValue*>(
-          local_state->GetMutableList(prefs::kDnsHostReferralList)->DeepCopy());
+      (local_state->FindPreference(prefs::kDnsHostReferralList)) ?

[jar (doing other things), 2010/12/13 20:27:29]

If this is where you migrate the data, perhaps it should be where you delete old
data (and not just copy it).

...thinking about this some more... 

This data is all "learned data" used for optimizing connections (and startup). 
It would not be  the worst thing if you simply discarded old data (i.e.,
critical stuff would be relearned quickly enough).

The critical point IMO is the discard of old data, both for efficiency, and for
security.  I'm not a profiles expert, so that is the detail I'm most curious
about.

[Miranda Callahan, 2010/12/14 01:03:49]

I think everything you say about deleting old data makes great sense.  Changed
the code to reflect this idea.

+    static_cast<ListValue*>(
+        local_state->GetMutableList(prefs::kDnsHostReferralList)->DeepCopy()) :
+    static_cast<ListValue*>(
+        user_prefs->GetMutableList(prefs::kDnsHostReferralList)->DeepCopy());
 
   g_browser_process->io_thread()->InitNetworkPredictor(
       prefetching_enabled, max_dns_queue_delay, max_parallel_resolves, urls,
@@ -479,8 +480,12 @@
   // This may catch secondary hostnames, pulled in by the homepages.  It will
   // also catch more of the "primary" home pages, since that was (presumably)
   // rendered first (and will be rendered first this time too).
+  // Migrate StartupPrefetchList from local_state to user prefs if needed.
   ListValue* startup_list =
-      local_state->GetMutableList(prefs::kDnsStartupPrefetchList);
+      (local_state->FindPreference(prefs::kDnsStartupPrefetchList)) ?
+    local_state->GetMutableList(prefs::kDnsStartupPrefetchList) :
+    user_prefs->GetMutableList(prefs::kDnsStartupPrefetchList);
+
   if (startup_list) {
     ListValue::iterator it = startup_list->begin();
     int format_version = -1;