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

net/proxy/proxy_script_fetcher_impl_unittest.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/proxy/proxy_script_fetcher_impl.h"
 
 #include <string>
 
 #include "base/file_path.h"
 #include "base/compiler_specific.h"
@@ skipping 165 matching lines @@
   virtual bool OnCanSetCookie(const URLRequest& request,
                               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);
 };
 
 }  // namespace
 
 class ProxyScriptFetcherImplTest : public PlatformTest {
  public:
   ProxyScriptFetcherImplTest()
       : test_server_(TestServer::TYPE_HTTP,
@@ skipping 277 matching lines @@
   {
     GURL url(kEncodedUrlBroken);
     string16 text;
     TestCompletionCallback callback;
     int result = pac_fetcher.Fetch(url, &text, callback.callback());
     EXPECT_EQ(ERR_FAILED, result);
   }
 }
 
 }  // namespace net