Flush socket pools and SPDY session pool properly on explicit requests and network changes.

net/base/mock_host_resolver.h

Index: net/base/mock_host_resolver.h
diff --git a/net/base/mock_host_resolver.h b/net/base/mock_host_resolver.h
index d08dc42cb20fe993d0aab4de4ce8f44f229f4026..661e2ddffd9144bfb94844b01b69026247f8e2f8 100644
--- a/net/base/mock_host_resolver.h
+++ b/net/base/mock_host_resolver.h
@@ -47,9 +47,12 @@ class MockHostResolverBase : public HostResolver {
   virtual void CancelRequest(RequestHandle req);
   virtual void AddObserver(Observer* observer);
   virtual void RemoveObserver(Observer* observer);
+  virtual void Flush();
 
   RuleBasedHostResolverProc* rules() { return rules_; }
 
+  const HostCache* cache() const { return impl_->cache(); }
+
   // Controls whether resolutions complete synchronously or asynchronously.
   void set_synchronous_mode(bool is_synchronous) {
     synchronous_mode_ = is_synchronous;