Change ProxyRules to handle ProxyLists rather than just single ProxyServer instances.

net/proxy/proxy_config.h

Index: net/proxy/proxy_config.h
diff --git a/net/proxy/proxy_config.h b/net/proxy/proxy_config.h
index 29619dff1e36ae3cd4ac02e96365b660b2817ef4..289aaee935f34d319d1ed5b8b194bf0c63a64977 100644
--- a/net/proxy/proxy_config.h
+++ b/net/proxy/proxy_config.h
@@ -11,6 +11,7 @@
 #include "net/base/net_export.h"
 #include "net/proxy/proxy_bypass_rules.h"
 #include "net/proxy/proxy_config_source.h"
+#include "net/proxy/proxy_list.h"
 #include "net/proxy/proxy_server.h"
 
 namespace base {
@@ -36,6 +37,8 @@ class NET_EXPORT ProxyConfig {
  public:
   // ProxyRules describes the "manual" proxy settings.
   // TODO(eroman): Turn this into a class.
+  // TODO(marq): Update the enum names; "TYPE_SINGLE_PROXY" really means
+  //             the same set of proxies are used for all requests.
   struct NET_EXPORT ProxyRules {
     enum Type {
       TYPE_NO_RULES,
@@ -52,31 +55,63 @@ class NET_EXPORT ProxyConfig {
       return type == TYPE_NO_RULES;
     }
 
-    // Sets |result| with the proxy to use for |url| based on the current rules.
+    // Sets |result| with the proxies to use for |url| based on the current
+    // rules.
     void Apply(const GURL& url, ProxyInfo* result) const;
 
     // Parses the rules from a string, indicating which proxies to use.
     //
     //   proxy-uri = [<proxy-scheme>"://"]<proxy-host>[":"<proxy-port>]
     //
-    // If the proxy to use depends on the scheme of the URL, can instead specify
-    // a semicolon separated list of:
+    //   proxy-uri-list = <proxy-uri>[","<proxy-uri-list>]
     //
-    //   <url-scheme>"="<proxy-uri>
+    //   url-scheme = "http" | "https" | "ftp" | "socks"
+    //
+    //   scheme-proxies = [<url-scheme>"="]<proxy-uri-list>
+    //
+    //   proxy-rules = scheme-proxies[";"<scheme-proxies>]
+    //
+    // Thus, the proxy-rules string should be a semicolon-separated list of
+    // ordered proxies that apply to a particular URL scheme. Unless specified,
+    // the proxy scheme for proxy-uris is assumed to be http.
+    //
+    // Some special cases:
+    //  * If the scheme is omitted from the first proxy list, that list applies
+    //    to all URL schemes and subsequent lists are ignored.
+    //  * If a scheme is omitted from any proxy list after a list where a scheme
+    //    has been provided, the list without a scheme is ignored.
+    //  * If the url-scheme is set to 'socks', that sets a fallback list that
+    //    to all otherwise unspecified url-schemes, however the default proxy-
+    //    scheme for proxy urls in the 'socks' list is understood to be
+    //    socks4:// if unspecified.
     //
     // For example:
     //   "http=foopy:80;ftp=foopy2"  -- use HTTP proxy "foopy:80" for http://
     //                                  URLs, and HTTP proxy "foopy2:80" for
     //                                  ftp:// URLs.
     //   "foopy:80"                  -- use HTTP proxy "foopy:80" for all URLs.
+    //   "foopy:80,bar,direct://"    -- use HTTP proxy "foopy:80" for all URLs,
+    //                                  failing over to "bar" if "foopy:80" is
+    //                                  unavailable, and after that using no
+    //                                  proxy.
     //   "socks4://foopy"            -- use SOCKS v4 proxy "foopy:1080" for all
     //                                  URLs.
+    //   "http=foop,socks5://bar.com -- use HTTP proxy "foopy" for http URLs,
+    //                                  and fail over to the SOCKS5 proxy
+    //                                  "bar.com" if "foop" is unavailable.
+    //   "http=foopy,direct://       -- use HTTP proxy "foopy" for http URLs,
+    //                                  and use no proxy if "foopy" is
+    //                                  unavailable.
+    //   "http=foopy;socks=foopy2   --  use HTTP proxy "foopy" for http URLs,
+    //                                  and use socks4://foopy2 for all other
+    //                                  URLs.
     void ParseFromString(const std::string& proxy_rules);
 
-    // Returns one of {&proxy_for_http, &proxy_for_https, &proxy_for_ftp,
-    // &fallback_proxy}, or NULL if there is no proxy to use.
+    // Returns one of {&proxies_for_http, &proxies_for_https, &proxies_for_ftp,
+    // &fallback_proxies}, or NULL if there is no proxy to use.
     // Should only call this if the type is TYPE_PROXY_PER_SCHEME.
-    const ProxyServer* MapUrlSchemeToProxy(const std::string& url_scheme) const;
+    const ProxyList* MapUrlSchemeToProxyList(
+        const std::string& url_scheme) const;
 
     // Returns true if |*this| describes the same configuration as |other|.
     bool Equals(const ProxyRules& other) const;
@@ -90,21 +125,22 @@ class NET_EXPORT ProxyConfig {
     Type type;
 
     // Set if |type| is TYPE_SINGLE_PROXY.
-    ProxyServer single_proxy;
+    ProxyList single_proxies;
 
     // Set if |type| is TYPE_PROXY_PER_SCHEME.
-    ProxyServer proxy_for_http;
-    ProxyServer proxy_for_https;
-    ProxyServer proxy_for_ftp;
+    ProxyList proxies_for_http;
+    ProxyList proxies_for_https;
+    ProxyList proxies_for_ftp;
 
-    // Used when there isn't a more specific per-scheme proxy server.
-    ProxyServer fallback_proxy;
+    // Used when a fallback has been defined and the url to be proxied doesn't
+    // match any of the standard schemes.
+    ProxyList fallback_proxies;
 
    private:
-    // Returns one of {&proxy_for_http, &proxy_for_https, &proxy_for_ftp}
+    // Returns one of {&proxies_for_http, &proxies_for_https, &proxies_for_ftp}
     // or NULL if it is a scheme that we don't have a mapping
     // for. Should only call this if the type is TYPE_PROXY_PER_SCHEME.
-    ProxyServer* MapUrlSchemeToProxyNoFallback(const std::string& scheme);
+    ProxyList* MapUrlSchemeToProxyListNoFallback(const std::string& scheme);
   };
 
   typedef int ID;