Reverting 19271.

Revert 19271, since it caused crash in reliability test. (dns prefetcher may still cancel requests on the host resolver during shutdown).
Review URL: http://codereview.chromium.org/149026

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@19289 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 9 insertions, 12 deletions

diff --git a/chrome/browser/net/chrome_url_request_context.cc b/chrome/browser/net/chrome_url_request_context.cc
index 19b35e4..1e01821 100644
--- a/chrome/browser/net/chrome_url_request_context.cc
+++ b/chrome/browser/net/chrome_url_request_context.cc
@@ -460,8 +460,9 @@ ChromeURLRequestContext::~ChromeURLRequestContext() {
 
   // Do not delete the proxy service in the case of OTR or media contexts, as
   // it is owned by the original URLRequestContext.
-  if (!is_off_the_record_ && !is_media_) {
+  if (!is_off_the_record_ && !is_media_)
     delete proxy_service_;
-    chrome_browser_net::FreeGlobalHostResolver();
-  }
+
+  // Do not delete host_resolver_; it will be freed by FreeGlobalHostResolver()
+  // during the teardown of DNS prefetching.
 }
diff --git a/chrome/browser/net/dns_global.cc b/chrome/browser/net/dns_global.cc
index f3b4c0e..9e4c8f6 100644
--- a/chrome/browser/net/dns_global.cc
+++ b/chrome/browser/net/dns_global.cc
@@ -38,9 +38,6 @@ static void DnsPrefetchMotivatedList(
 // static
 const size_t DnsPrefetcherInit::kMaxConcurrentLookups = 8;
 
-// Host resolver shared by DNS prefetcher, and the main URLRequestContext.
-static net::HostResolver* global_host_resolver = NULL;
-
 //------------------------------------------------------------------------------
 // This section contains all the globally accessable API entry points for the
 // DNS Prefetching feature.
@@ -438,13 +435,9 @@ void InitDnsPrefetch(size_t max_concurrent, PrefService* user_prefs) {
 }
 
 void EnsureDnsPrefetchShutdown() {
-  if (NULL != dns_master) {
+  if (NULL != dns_master)
     dns_master->Shutdown();
-
-    // Unregister the resolution observer added by InitDnsPrefetch()
-    if (global_host_resolver)
-      global_host_resolver->RemoveObserver(&dns_resolution_observer);
-  }
+  FreeGlobalHostResolver();
 }
 
 void FreeDnsPrefetchResources() {
@@ -461,6 +454,9 @@ static void DiscardAllPrefetchState() {
 
 //------------------------------------------------------------------------------
 
+// Host resolver shared by DNS prefetcher, and the main URLRequestContext.
+static net::HostResolver* global_host_resolver = NULL;
+
 net::HostResolver* GetGlobalHostResolver() {
   // Called from UI thread.
   if (!global_host_resolver) {