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

chrome/browser/extensions/api/proxy/proxy_api_helpers.h

Index: chrome/browser/extensions/api/proxy/proxy_api_helpers.h
diff --git a/chrome/browser/extensions/api/proxy/proxy_api_helpers.h b/chrome/browser/extensions/api/proxy/proxy_api_helpers.h
index 064b5c2565b57c9b1c23bda06251b48fdf30d678..15946c0a7ad36ad9097a785859c7c6619590be52 100644
--- a/chrome/browser/extensions/api/proxy/proxy_api_helpers.h
+++ b/chrome/browser/extensions/api/proxy/proxy_api_helpers.h
@@ -116,9 +116,9 @@ base::DictionaryValue* CreateProxyRulesDict(
     const ProxyConfigDictionary& proxy_config);
 
 // Creates and returns a ProxyServer dictionary as defined in the extension API
-// with values from a net::ProxyServer object. Never returns NULL. Ownership is
-// passed to the caller.
-base::DictionaryValue* CreateProxyServerDict(const net::ProxyServer& proxy);
+// with values from a net::ProxyList containing exactly one net::ProxyServer
+// object. Never returns NULL. Ownership is passed to the caller.
+base::DictionaryValue* CreateProxyServerDict(const net::ProxyList& proxies);
 
 // Creates and returns a PacScript dictionary as defined in the extension API
 // with the values of a ProxyconfigDictionary configured for pac scripts.