Revert of Moving proxy resolution logic out of NetworkDelegate and into ProxyDelegate

net/base/network_delegate_impl.h

Index: net/base/network_delegate_impl.h
diff --git a/net/base/network_delegate_impl.h b/net/base/network_delegate_impl.h
index 150e65c380b4107f3db757effccc6e34bef1a52a..8a0b007f3d836cac5440304e8775a39d79d9c1d8 100644
--- a/net/base/network_delegate_impl.h
+++ b/net/base/network_delegate_impl.h
@@ -24,6 +24,8 @@
 class HttpRequestHeaders;
 class HttpResponseHeaders;
 class ProxyInfo;
+class ProxyServer;
+class ProxyService;
 class URLRequest;
 
 class NET_EXPORT NetworkDelegateImpl : public NetworkDelegate {
@@ -50,6 +52,20 @@
   int OnBeforeURLRequest(URLRequest* request,
                          const CompletionCallback& callback,
                          GURL* new_url) override;
+
+  // Called as the proxy is being resolved for |url|. Allows the delegate to
+  // override the proxy resolution decision made by ProxyService. The delegate
+  // may override the decision by modifying the ProxyInfo |result|.
+  void OnResolveProxy(const GURL& url,
+                      int load_flags,
+                      const ProxyService& proxy_service,
+                      ProxyInfo* result) override;
+
+  // Called when use of |bad_proxy| fails due to |net_error|. |net_error| is
+  // the network error encountered, if any, and OK if the fallback was
+  // for a reason other than a network error (e.g. the proxy service was
+  // explicitly directed to skip a proxy).
+  void OnProxyFallback(const ProxyServer& bad_proxy, int net_error) override;
 
   // Called right before the HTTP headers are sent. Allows the delegate to
   // read/write |headers| before they get sent out. |callback| and |headers| are