PPAPI: Get TrackedCallback ready for running on non-main threads.

ppapi/proxy/ppb_url_loader_proxy.cc

 // 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.
 
 #include "ppapi/proxy/ppb_url_loader_proxy.h"
 
 #include <algorithm>
 #include <deque>
 #include <vector>
 
@@ skipping 333 matching lines @@
     if (result > bytes_to_return) {
       // Save what remains to be copied when ReadResponseBody is called again.
       buffer_.insert(buffer_.end(),
                      data + bytes_to_return,
                      data + result);
     }
 
     result = bytes_to_return;
   }
 
-  TrackedCallback::ClearAndRun(&current_callback_, result);
+  current_callback_->Run(result);
 }
 
 void URLLoader::CallbackComplete(int32_t result) {
-  TrackedCallback::ClearAndRun(&current_callback_, result);
+  current_callback_->Run(result);
 }
 
 void URLLoader::PopBuffer(void* output_buffer, int32_t output_size) {
   CHECK(output_size <= static_cast<int32_t>(buffer_.size()));
   std::copy(buffer_.begin(),
             buffer_.begin() + output_size,
             static_cast<char*>(output_buffer));
   buffer_.erase(buffer_.begin(),
                 buffer_.begin() + output_size);
 }
@@ skipping 246 matching lines @@
 }
 
 void PPB_URLLoader_Proxy::OnCallback(int32_t result,
                                      const HostResource& resource) {
   dispatcher()->Send(new PpapiMsg_PPBURLLoader_CallbackComplete(
       API_ID_PPB_URL_LOADER, resource, result));
 }
 
 }  // namespace proxy
 }  // namespace ppapi