Ensure that even if the HostResolver outlives the IO thread, its jobs will no...

net/base/host_resolver.cc

Index: net/base/host_resolver.cc
===================================================================
--- net/base/host_resolver.cc	(revision 19453)
+++ net/base/host_resolver.cc	(working copy)
@@ -398,7 +398,8 @@
 //-----------------------------------------------------------------------------
 
 HostResolver::HostResolver(int max_cache_entries, int cache_duration_ms)
-    : cache_(max_cache_entries, cache_duration_ms), next_request_id_(0) {
+    : cache_(max_cache_entries, cache_duration_ms), next_request_id_(0),
+      shutdown_(false) {
 #if defined(OS_WIN)
   EnsureWinsockInit();
 #endif
@@ -421,6 +422,9 @@
                           AddressList* addresses,
                           CompletionCallback* callback,
                           Request** out_req) {
+  if (shutdown_)
+    return ERR_UNEXPECTED;
+
   // Choose a unique ID number for observers to see.
   int request_id = next_request_id_++;
 
@@ -517,6 +521,15 @@
   observers_.erase(it);
 }
 
+void HostResolver::Shutdown() {
+  shutdown_ = true;
+
+  // Cancel the outstanding jobs.
+  for (JobMap::iterator it = jobs_.begin(); it != jobs_.end(); ++it)
+    it->second->Cancel();
+  jobs_.clear();
+}
+
 void HostResolver::AddOutstandingJob(Job* job) {
   scoped_refptr<Job>& found_job = jobs_[job->host()];
   DCHECK(!found_job);