6 files changed, 17 insertions, 14 deletions
diff --git a/chrome/browser/io_thread.cc b/chrome/browser/io_thread.cc
index 4ee6814..f4d4698 100644
--- a/chrome/browser/io_thread.cc
+++ b/chrome/browser/io_thread.cc
@@ -153,9 +153,8 @@ void IOThread::CleanUp() {
   }
 
   // TODO(eroman): hack for http://crbug.com/15513
-  if (globals_->host_resolver->IsHostResolverImpl()) {
-    static_cast<net::HostResolverImpl*>(
-        globals_->host_resolver.get())->Shutdown();
+  if (globals_->host_resolver->GetAsHostResolverImpl()) {
+    globals_->host_resolver.get()->GetAsHostResolverImpl()->Shutdown();
   }
 
   delete globals_;
@@ -210,9 +209,9 @@ void IOThread::ChangedToOnTheRecordOnIOThread() {
 
   // Clear the host cache to avoid showing entries from the OTR session
   // in about:net-internals.
-  if (globals_->host_resolver->IsHostResolverImpl()) {
-    net::HostCache* host_cache = static_cast<net::HostResolverImpl*>(
-        globals_->host_resolver.get())->cache();
+  if (globals_->host_resolver->GetAsHostResolverImpl()) {
+    net::HostCache* host_cache =
+        globals_->host_resolver.get()->GetAsHostResolverImpl()->cache();
     if (host_cache)
       host_cache->clear();
   }
diff --git a/net/base/host_resolver.h b/net/base/host_resolver.h
index da431f3..c4cdef6 100644
--- a/net/base/host_resolver.h
+++ b/net/base/host_resolver.h
@@ -19,6 +19,7 @@ namespace net {
 
 class AddressList;
 class HostCache;
+class HostResolverImpl;
 class LoadLog;
 class NetworkChangeNotifier;
 
@@ -161,10 +162,10 @@ class HostResolver : public base::RefCountedThreadSafe<HostResolver> {
   // AF_INET6 by passing in ADDRESS_FAMILY_IPV6.
   virtual void SetDefaultAddressFamily(AddressFamily address_family) {}
 
-  // Returns true if this HostResolver is an instance of HostResolverImpl.
-  // Used primarily to expose additional functionality on the
-  // about:net-internals page.
-  virtual bool IsHostResolverImpl() { return false; }
+  // Returns |this| cast to a HostResolverImpl*, or NULL if the subclass
+  // is not compatible with HostResolverImpl. Used primarily to expose
+  // additional functionality on the about:net-internals page.
+  virtual HostResolverImpl* GetAsHostResolverImpl() { return NULL; }
 
  protected:
   friend class base::RefCountedThreadSafe<HostResolver>;
diff --git a/net/base/host_resolver_impl.h b/net/base/host_resolver_impl.h
index 6499b3e..3e273cd 100644
--- a/net/base/host_resolver_impl.h
+++ b/net/base/host_resolver_impl.h
@@ -92,7 +92,7 @@ class HostResolverImpl : public HostResolver,
     default_address_family_ = address_family;
   }
 
-  virtual bool IsHostResolverImpl() { return true; }
+  virtual HostResolverImpl* GetAsHostResolverImpl() { return this; }
 
   // TODO(eroman): hack for http://crbug.com/15513
   void Shutdown();
diff --git a/net/base/mapped_host_resolver.cc b/net/base/mapped_host_resolver.cc
index 3624a9b..164d7c6 100644
--- a/net/base/mapped_host_resolver.cc
+++ b/net/base/mapped_host_resolver.cc
@@ -37,6 +37,10 @@ void MappedHostResolver::RemoveObserver(Observer* observer) {
   impl_->RemoveObserver(observer);
 }
 
+HostResolverImpl* MappedHostResolver::GetAsHostResolverImpl() {
+  return impl_->GetAsHostResolverImpl();
+}
+
 MappedHostResolver::~MappedHostResolver() {
 }
 
diff --git a/net/base/mapped_host_resolver.h b/net/base/mapped_host_resolver.h
index af78a9c..a637a40 100644
--- a/net/base/mapped_host_resolver.h
+++ b/net/base/mapped_host_resolver.h
@@ -32,6 +32,7 @@ class MappedHostResolver : public HostResolver {
   virtual void CancelRequest(RequestHandle req);
   virtual void AddObserver(Observer* observer);
   virtual void RemoveObserver(Observer* observer);
+  virtual HostResolverImpl* GetAsHostResolverImpl();
 
   // Adds a rule to this mapper. The format of the rule can be one of:
   //
diff --git a/net/url_request/url_request_view_net_internals_job.cc b/net/url_request/url_request_view_net_internals_job.cc
index 15986f6..38349a4 100644
--- a/net/url_request/url_request_view_net_internals_job.cc
+++ b/net/url_request/url_request_view_net_internals_job.cc
@@ -51,9 +51,7 @@ void DrawCommandButton(const std::string& title,
 //------------------------------------------------------------------------------
 
 net::HostResolverImpl* GetHostResolverImpl(URLRequestContext* context) {
-  if (context->host_resolver()->IsHostResolverImpl())
-    return static_cast<net::HostResolverImpl*> (context->host_resolver());
-  return NULL;
+  return context->host_resolver()->GetAsHostResolverImpl();
 }
 
 net::HostCache* GetHostCache(URLRequestContext* context) {