Add Finch experiment for selectively bypassing proxies.

chrome/browser/net/chrome_network_delegate.h

Index: chrome/browser/net/chrome_network_delegate.h
diff --git a/chrome/browser/net/chrome_network_delegate.h b/chrome/browser/net/chrome_network_delegate.h
index a67f77375b3da36855240b053f1a7b55cfbe0dc8..95409849b7628969169de6817a532f3b1450dcde 100644
--- a/chrome/browser/net/chrome_network_delegate.h
+++ b/chrome/browser/net/chrome_network_delegate.h
@@ -48,6 +48,7 @@ class InfoMap;
 
 namespace net {
 class URLRequest;
+class ProxyInfo;
 }
 
 namespace policy {
@@ -123,6 +124,16 @@ class ChromeNetworkDelegate : public net::NetworkDelegate {
     data_reduction_proxy_params_ = params;
   }
 
+  // Provides an opportunity to interpose on proxy resolution. Called before
+  // ProxyService.ResolveProxy() returns. |proxy_info| contains information
+  // about the proxy being used, and may be modified by this callback.
+  typedef base::Callback<void(const GURL& url, int load_flags,
+                              net::ProxyInfo* result)> OnResolveProxyHandler;
+
+  void set_on_resolve_proxy_handler(OnResolveProxyHandler* handler) {
+    on_resolve_proxy_handler_ = handler;
+  }
+
   // Adds the Client Hints header to HTTP requests.
   void SetEnableClientHints();
 
@@ -159,6 +170,8 @@ class ChromeNetworkDelegate : public net::NetworkDelegate {
   virtual int OnBeforeURLRequest(net::URLRequest* request,
                                  const net::CompletionCallback& callback,
                                  GURL* new_url) OVERRIDE;
+  virtual void OnResolveProxy(
+      const GURL& url, int load_flags, net::ProxyInfo* result) OVERRIDE;
   virtual int OnBeforeSendHeaders(net::URLRequest* request,
                                   const net::CompletionCallback& callback,
                                   net::HttpRequestHeaders* headers) OVERRIDE;
@@ -250,6 +263,8 @@ class ChromeNetworkDelegate : public net::NetworkDelegate {
 
   data_reduction_proxy::DataReductionProxyParams* data_reduction_proxy_params_;
 
+  OnResolveProxyHandler* on_resolve_proxy_handler_;
+
   DISALLOW_COPY_AND_ASSIGN(ChromeNetworkDelegate);
 };