Make net::HostResolver refcounted.

This way it can be properly shared between the url request contexts, and the dns prefetcher, and dns observer.

BUG=http://crbug.com/14664
TEST=existing unit tests.

Review URL: http://codereview.chromium.org/149053

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@19425 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 6 insertions, 10 deletions

diff --git a/chrome/browser/net/dns_global.cc b/chrome/browser/net/dns_global.cc
index 9e4c8f6..4b821c6 100644
--- a/chrome/browser/net/dns_global.cc
+++ b/chrome/browser/net/dns_global.cc
@@ -435,9 +435,13 @@ void InitDnsPrefetch(size_t max_concurrent, PrefService* user_prefs) {
 }
 
 void EnsureDnsPrefetchShutdown() {
-  if (NULL != dns_master)
+  if (NULL != dns_master) {
     dns_master->Shutdown();
-  FreeGlobalHostResolver();
+
+    // Stop observing DNS resolutions. Note that dns_master holds a reference
+    // to the global host resolver, so is guaranteed to be live.
+    GetGlobalHostResolver()->RemoveObserver(&dns_resolution_observer);
+  }
 }
 
 void FreeDnsPrefetchResources() {
@@ -469,14 +473,6 @@ net::HostResolver* GetGlobalHostResolver() {
   return global_host_resolver;
 }
 
-void FreeGlobalHostResolver() {
-  if (global_host_resolver) {
-    // Called from IO thread.
-    delete global_host_resolver;
-    global_host_resolver = NULL;
-  }
-}
-
 //------------------------------------------------------------------------------
 // Functions to handle saving of hostnames from one session to the next, to
 // expedite startup times.