PPAPI: Make blocking completion callbacks work.

ppapi/shared_impl/private/ppb_host_resolver_shared.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef PPAPI_SHARED_IMPL_PRIVATE_PPB_HOST_RESOLVER_SHARED_H_
 #define PPAPI_SHARED_IMPL_PRIVATE_PPB_HOST_RESOLVER_SHARED_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 32 matching lines @@
   virtual ~PPB_HostResolver_Shared();
 
   // Resource overrides.
   virtual PPB_HostResolver_Private_API*
       AsPPB_HostResolver_Private_API() OVERRIDE;
 
   // PPB_HostResolver_Private_API implementation.
   virtual int32_t Resolve(const char* host,
                           uint16_t port,
                           const PP_HostResolver_Private_Hint* hint,
-                          PP_CompletionCallback callback) OVERRIDE;
+                          scoped_refptr<TrackedCallback> callback) OVERRIDE;
   virtual PP_Var GetCanonicalName() OVERRIDE;
   virtual uint32_t GetSize() OVERRIDE;
   virtual bool GetNetAddress(uint32_t index,
                              PP_NetAddress_Private* address) OVERRIDE;
 
   void OnResolveCompleted(bool succeeded,
                           const std::string& canonical_name,
                           const NetAddressList& net_address_list);
 
   // Send functions that need to be implemented differently for the
@@ skipping 11 matching lines @@
 
   std::string canonical_name_;
   NetAddressList net_address_list_;
 
   DISALLOW_COPY_AND_ASSIGN(PPB_HostResolver_Shared);
 };
 
 }  // namespace ppapi
 
 #endif  // PPAPI_SHARED_IMPL_PRIVATE_PPB_HOST_RESOLVER_SHARED_H_