Update from https://crrev.com/308331

net/test/embedded_test_server/embedded_test_server.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/test/embedded_test_server/embedded_test_server.h"
 
 #include "base/bind.h"
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/message_loop/message_loop.h"
@@ skipping 31 matching lines @@
   DISALLOW_COPY_AND_ASSIGN(CustomHttpResponse);
 };
 
 // Handles |request| by serving a file from under |server_root|.
 scoped_ptr<HttpResponse> HandleFileRequest(
     const base::FilePath& server_root,
     const HttpRequest& request) {
   // This is a test-only server. Ignore I/O thread restrictions.
   base::ThreadRestrictions::ScopedAllowIO allow_io;
 
+  std::string relative_url(request.relative_url);
+  // A proxy request will have an absolute path. Simulate the proxy by stripping
+  // the scheme, host, and port.
+  GURL relative_gurl(relative_url);
+  if (relative_gurl.is_valid())
+    relative_url = relative_gurl.PathForRequest();
+
   // Trim the first byte ('/').
-  std::string request_path(request.relative_url.substr(1));
+  std::string request_path = relative_url.substr(1);
 
   // Remove the query string if present.
   size_t query_pos = request_path.find('?');
   if (query_pos != std::string::npos)
     request_path = request_path.substr(0, query_pos);
 
   base::FilePath file_path(server_root.AppendASCII(request_path));
   std::string file_contents;
   if (!base::ReadFileToString(file_path, &file_contents))
     return scoped_ptr<HttpResponse>();
@@ skipping 282 matching lines @@
           FROM_HERE, closure, run_loop.QuitClosure())) {
     return false;
   }
   run_loop.Run();
 
   return true;
 }
 
 }  // namespace test_server
 }  // namespace net