Implement exponential back-off mechanism.

net/url_request/url_request_throttler_header_adapter.cc

Index: net/url_request/url_request_throttler_header_adapter.cc
diff --git a/net/url_request/url_request_throttler_header_adapter.cc b/net/url_request/url_request_throttler_header_adapter.cc
new file mode 100644
index 0000000000000000000000000000000000000000..e453071c54eb2f7c2b22cce8f96c645c9ee5fd17
--- /dev/null
+++ b/net/url_request/url_request_throttler_header_adapter.cc
@@ -0,0 +1,27 @@
+// Copyright (c) 2010 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_throttler_header_adapter.h"
+
+#include "net/http/http_response_headers.h"
+
+namespace net {
+
+URLRequestThrottlerHeaderAdapter::URLRequestThrottlerHeaderAdapter(
+    net::HttpResponseHeaders* headers)
+    : response_header_(headers) {
+}
+
+std::string URLRequestThrottlerHeaderAdapter::GetNormalizedValue(
+    const std::string& key) const {
+  std::string return_value;
+  response_header_->GetNormalizedHeader(key, &return_value);
+  return return_value;
+}
+
+int URLRequestThrottlerHeaderAdapter::GetResponseCode() const {
+  return response_header_->response_code();
+}
+
+}  // namespace net