Ensure that OCSPIOLoop is associated with right thread if restarted.

net/ocsp/nss_ocsp.cc

Index: net/ocsp/nss_ocsp.cc
diff --git a/net/ocsp/nss_ocsp.cc b/net/ocsp/nss_ocsp.cc
index cabda31dd046c86ee5ce96dd1e7f2b28cae1673c..5412cba46a7a804beb80c130504cd5d1fc54b4f3 100644
--- a/net/ocsp/nss_ocsp.cc
+++ b/net/ocsp/nss_ocsp.cc
@@ -78,6 +78,20 @@ class OCSPIOLoop {
   void AddRequest(OCSPRequestSession* request);
   void RemoveRequest(OCSPRequestSession* request);
 
+  // Clears internal state and calls |StartUsing()|. Should be called only in
+  // the context of testing.
+  void ReuseForTesting() {
+    {
+      base::AutoLock autolock(lock_);
+      DCHECK(MessageLoopForIO::current());
+      thread_checker_.DetachFromThread();
+      thread_checker_.CalledOnValidThread();
+      shutdown_ = false;
+      used_ = false;
+    }
+    StartUsing();
+  }
+
  private:
   friend struct base::DefaultLazyInstanceTraits<OCSPIOLoop>;
 
@@ -934,6 +948,10 @@ void ShutdownNSSHttpIO() {
   g_ocsp_io_loop.Get().Shutdown();
 }
 
+void ResetNSSHttpIOForTesting() {
+  g_ocsp_io_loop.Get().ReuseForTesting();
+}
+
 // This function would be called before NSS initialization.
 void SetURLRequestContextForNSSHttpIO(URLRequestContext* request_context) {
   pthread_mutex_lock(&g_request_context_lock);