Simple fallback implementation.

chrome/browser/net/spdyproxy/data_reduction_proxy_settings.h

Index: chrome/browser/net/spdyproxy/data_reduction_proxy_settings.h
diff --git a/chrome/browser/net/spdyproxy/data_reduction_proxy_settings.h b/chrome/browser/net/spdyproxy/data_reduction_proxy_settings.h
index f066d661713d4b39fbef8b3e680667d43f6546dc..6480378cc1d4fb0ba2fca20a3fa9bc5f51f77435 100644
--- a/chrome/browser/net/spdyproxy/data_reduction_proxy_settings.h
+++ b/chrome/browser/net/spdyproxy/data_reduction_proxy_settings.h
@@ -18,6 +18,9 @@
 class PrefService;
 
 namespace net {
+class AuthChallengeInfo;
+class HostPortPair;
+class HttpNetworkSession;
 class URLFetcher;
 }
 
@@ -42,12 +45,17 @@ class DataReductionProxySettings
       public net::NetworkChangeNotifier::IPAddressObserver {
  public:
   typedef std::vector<long long> ContentLengthList;
+  typedef std::vector<net::HostPortPair> DataReductionProxyList;
 
   DataReductionProxySettings();
   virtual ~DataReductionProxySettings();
 
   void InitDataReductionProxySettings();
 
+  // If proxy authentication is compiled in, pre-cache authentication
+  // keys for all configured proxies in |session|.
+  void InitDataReductionProxySession(net::HttpNetworkSession* session);
+
   // Add a host pattern to bypass. This should follow the same syntax used
   // in net::ProxyBypassRules; that is, a hostname pattern, a hostname suffix
   // pattern, an IP literal, a CIDR block, or the magic string '<local>'.
@@ -75,8 +83,20 @@ class DataReductionProxySettings
   // Returns the URL of the data reduction proxy.
   std::string GetDataReductionProxyOrigin();
 
-  // Returns a configuration string for the proxy.
-  std::string GetDataReductionProxyAuth();
+  // Returns the URL of the fallback data reduction proxy.
+  std::string GetDataReductionProxyFallback();
+
+  // Returns a vector of HostPortPairs for all configured proxies.

[bengr, 2013/10/22 17:49:30]

It seems a little strange to return a vector when we have at most a pair.

[marq (ping after 24h), 2013/10/22 21:18:01]

It's somewhat cleaner (to my mind) to write generic code that operates on one or
two objects using a vector than to repeatedly check if there's a second object
or not. I'll see if the pair looks less awkward to me.

+  DataReductionProxyList GetDataReductionProxies();
+
+  // Returns true if |auth_info| represents an authentication challenge from
+  // a compatible, configured proxy.
+  bool IsAcceptableAuthChallenge(net::AuthChallengeInfo* auth_info);
+
+  // Returns a UTF16 string suitable for use as an authentication token in
+  // response to the challenge represented by |auth_info|. If the token can't
+  // be correctly generated for |auth_info|, returns an empty UTF16 string.
+  base::string16 GetTokenForAuthChallenge(net::AuthChallengeInfo* auth_info);
 
   // Returns true if the proxy is enabled.
   bool IsDataReductionProxyEnabled();
@@ -113,8 +133,6 @@ class DataReductionProxySettings
   virtual PrefService* GetOriginalProfilePrefs();
   virtual PrefService* GetLocalStatePrefs();
 
-  std::string GetDataReductionProxyOriginHostPort();
-
   bool IsProxyOriginSetOnCommandLine();
   void GetContentLengths(unsigned int days,
                          int64* original_content_length,
@@ -146,10 +164,18 @@ class DataReductionProxySettings
   // Accessor for unit tests.
   std::vector<std::string> BypassRules() { return bypass_rules_;}
 
+  // Accessors for default hostnames, virtual for testing.
+  virtual std::string GetDefaultProxyHost();
+  virtual std::string GetDefaultFallbackProxyHost();
+
  private:
   friend class DataReductionProxySettingsTestBase;
   friend class DataReductionProxySettingsTest;
   FRIEND_TEST_ALL_PREFIXES(DataReductionProxySettingsTest,
+                           TestAuthHashGeneration);
+  FRIEND_TEST_ALL_PREFIXES(DataReductionProxySettingsTest,
+                           TestAuthHashGenerationWithOriginSetViaSwitch);
+  FRIEND_TEST_ALL_PREFIXES(DataReductionProxySettingsTest,
                            TestResetDataReductionStatistics);
   FRIEND_TEST_ALL_PREFIXES(DataReductionProxySettingsTest,
                            TestIsProxyEnabledOrManaged);
@@ -185,6 +211,11 @@ class DataReductionProxySettings
   void ProbeWhetherDataReductionProxyIsAvailable();
   std::string GetProxyCheckURL();
 
+  // Returns a UTF16 string that's the hash of the configured authentication
+  // key and |salt|. Returns an empty UTF16 string if no key is configured or
+  // the data reduction proxy feature isn't available.
+  base::string16 AuthHashForSalt(int64 salt);
+
   std::vector<std::string> bypass_rules_;
 
   // Indicate whether a user has turned on the data reduction proxy previously