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..faee16db8312be93fff36d34a027b3c1897cca0b 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 +55,54 @@ 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>
+    // If all URLs should use the same proxies, |proxy_rules| should be a

[eroman, 2013/03/05 01:55:55]

[optional] Your current wording is fine. Another way to think about this is that
the grammar takes a semi-colon separated list of ordered proxies that apply to a
particular url-scheme. If the <url-scheme>"=" prefix is left off, then it is
assumed to apply to all URL schemes (i.e. the "fallback" proxies). If the
url-scheme is set to "socks" than this also means a fallback list that applies
to all url-schemes, however the default proxy-scheme when parsing the elements
is understood to be socks4:// if left unspecified.

  X [
X = [<url-scheme>]

[marq_use_my_chromium_address, 2013/03/05 22:52:40]

Done.

+    // <proxy-uri-list>.
+    //
+    // If the proxy to use depends on the scheme of the URL, |proxy_rules| can
+    // instead be a a semicolon separated list of:
+    //
+    //   <url-scheme>"="<proxy-uri-list>
+    //
+    // If 'socks' is specified as a scheme, any schemes left without proxies
+    // specified will have that 'socks' server added.

[eroman, 2013/03/05 01:55:55]

This is best understood in terms of fallback-proxy list, since non-socks proxy
servers can also be enumerated in here.

[marq_use_my_chromium_address, 2013/03/05 22:52:40]

Done.

     //
     // 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=foopy,bar.com         -- use HTTP proxy "foopy" for http URLs,

[eroman, 2013/03/05 01:55:55]

To make this example more interesting, I suggest changing it to:

http=foop,socks5://bar.com

[marq_use_my_chromium_address, 2013/03/05 22:52:40]

Done.

+    //                                  and fail over to "bar.com" if "foopy"
+    //                                  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 +116,22 @@ 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;