Convert the PluginResource to be refcounted.

ppapi/proxy/ppb_context_3d_proxy.cc

 // Copyright (c) 2011 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.
 
 #include "ppapi/proxy/ppb_context_3d_proxy.h"
 
 #include "base/hash_tables.h"
 #include "gpu/command_buffer/client/gles2_cmd_helper.h"
 #include "gpu/command_buffer/client/gles2_implementation.h"
 #include "ppapi/c/pp_errors.h"
@@ skipping 560 matching lines @@
   } else {
     attribs.push_back(0);
   }
 
   HostResource result;
   dispatcher->Send(new PpapiHostMsg_PPBContext3D_Create(
       INTERFACE_ID_PPB_CONTEXT_3D, instance, config, attribs, &result));
 
   if (result.is_null())
     return 0;
-  linked_ptr<Context3D> context_3d(new Context3D(result));
+  scoped_refptr<Context3D> context_3d(new Context3D(result));
   if (!context_3d->CreateImplementation())
     return 0;
   return PluginResourceTracker::GetInstance()->AddResource(context_3d);
 }
 
 bool PPB_Context3D_Proxy::OnMessageReceived(const IPC::Message& msg) {
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP(PPB_Context3D_Proxy, msg)
     IPC_MESSAGE_HANDLER(PpapiHostMsg_PPBContext3D_Create,
                         OnMsgCreate)
@@ skipping 127 matching lines @@
   uint32_t shm_size = 0;
   if (enter.succeeded() &&
       enter.object()->GetTransferBuffer(id, &shm_handle, &shm_size)) {
     *transfer_buffer = TransportSHMHandleFromInt(dispatcher(), shm_handle);
     *size = shm_size;
   }
 }
 
 }  // namespace proxy
 }  // namespace pp