Introduce a delegate to avoid hardcoding "chrome-extension" in net/.

net/url_request/url_request_context_builder.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 "net/url_request/url_request_context_builder.h"
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
@@ skipping 83 matching lines @@
                               const std::string& cookie_line,
                               CookieOptions* options) OVERRIDE {
     return true;
   }
 
   virtual bool OnCanAccessFile(const net::URLRequest& request,
                                const FilePath& path) const OVERRIDE {
     return true;
   }
 
+  virtual bool OnCanThrottleRequest(const URLRequest& request) const OVERRIDE {
+    return false;
+  }
+
   DISALLOW_COPY_AND_ASSIGN(BasicNetworkDelegate);
 };
 
 class BasicURLRequestContext : public URLRequestContext {
  public:
   BasicURLRequestContext()
       : cache_thread_("Cache Thread"),
         file_thread_("File Thread"),
         ALLOW_THIS_IN_INITIALIZER_LIST(storage_(this)) {}
 
@@ skipping 158 matching lines @@
     http_transaction_factory = new HttpNetworkLayer(network_session);
   }
   storage->set_http_transaction_factory(http_transaction_factory);
 
   // TODO(willchan): Support sdch.
 
   return context;
 }
 
 }  // namespace net