Modify data_reduction_proxy_header to support tamper detection logic.

components/data_reduction_proxy/common/data_reduction_proxy_headers.h

 // Copyright 2014 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.
 
 #ifndef COMPONENTS_DATA_REDUCTION_PROXY_COMMON_DATA_REDUCTION_PROXY_HEADERS_H_
 #define COMPONENTS_DATA_REDUCTION_PROXY_COMMON_DATA_REDUCTION_PROXY_HEADERS_H_
 
 #include <string>
 
 #include "base/macros.h"
 #include "base/time/time.h"
 #include "net/http/http_response_headers.h"
 #include "net/proxy/proxy_service.h"
 
 using net::ProxyService;
 
 namespace data_reduction_proxy {
 
+extern const char kChromeProxyActionFingerprintChromeProxy[];
+extern const char kChromeProxyActionFingerprintVia[];
+extern const char kChromeProxyActionFingerprintOtherHeaders[];
+extern const char kChromeProxyActionFingerprintContentLength[];
+
 // Contains instructions contained in the Chrome-Proxy header.
 struct DataReductionProxyInfo {
   DataReductionProxyInfo() : bypass_all(false) {}
 
   // True if Chrome should bypass all available data reduction proxies. False
   // if only the currently connected data reduction proxy should be bypassed.
   bool bypass_all;
 
   // Amount of time to bypass the data reduction proxy or proxies.
   base::TimeDelta bypass_duration;
 };
 
 // Returns true if the Chrome-Proxy header is present and contains a bypass
 // delay. Sets |proxy_info->bypass_duration| to the specified delay if greater
 // than 0, and to 0 otherwise to indicate that the default proxy delay
 // (as specified in |ProxyList::UpdateRetryInfoOnFallback|) should be used.
 // If all available data reduction proxies should by bypassed, |bypass_all| is
 // set to true. |proxy_info| must be non-NULL.
 bool GetDataReductionProxyInfo(
     const net::HttpResponseHeaders* headers,
     DataReductionProxyInfo* proxy_info);
 
 // Returns true if the response contain the data reduction proxy Via header
-// value. Used to check the integrity of data reduction proxy responses.
-bool HasDataReductionProxyViaHeader(const net::HttpResponseHeaders* headers);
+// value. If non-NULL, sets |has_intermediary| to true if another server added
+// a Via header after the data reduction proxy, and to false otherwise. Used to
+// check the integrity of data reduction proxy responses and whether there are
+// other middleboxes between data reduction proxy and chrome.
+bool HasDataReductionProxyViaHeader(const net::HttpResponseHeaders* headers,
+                                    bool* has_intermediary);
 
 // Returns the reason why the Chrome proxy should be bypassed or not, and
 // populates |proxy_info| with information on how long to bypass if
 // applicable.
 ProxyService::DataReductionProxyBypassType GetDataReductionProxyBypassType(
     const net::HttpResponseHeaders* headers,
     DataReductionProxyInfo* proxy_info);
 
+// Searches for the specified Chrome-Proxy action, and if present saves its
+// value as a string in |action_value|. Only keeps the first one and ignores

[bolian, 2014/07/28 22:59:18]

s/keeps/returns/

[xingx1, 2014/07/29 00:47:40]

Done.

+// the rest if multiple actions match |action_prefix|.
+bool GetDataReductionProxyActionValue(
+    const net::HttpResponseHeaders* headers,
+    const std::string& action_prefix,
+    std::string* action_value);
+
 // Searches for the specified Chrome-Proxy action, and if present interprets
 // its value as a duration in seconds.
 bool GetDataReductionProxyBypassDuration(
     const net::HttpResponseHeaders* headers,
     const std::string& action_prefix,
     base::TimeDelta* duration);
 
 }  // namespace data_reduction_proxy
 #endif  // COMPONENTS_DATA_REDUCTION_PROXY_COMMON_DATA_REDUCTION_PROXY_HEADERS_H_