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 976e1bbbb5256eb10bef925dd50b8279cb3178d1..436c69d3a16f6378a2b22aebcb08947bda7f44cd 100644
--- a/chrome/browser/net/chrome_network_delegate.h
+++ b/chrome/browser/net/chrome_network_delegate.h
@@ -142,6 +142,19 @@ class ChromeNetworkDelegate : public net::NetworkDelegate {
     data_reduction_proxy_auth_request_handler_ = handler;
   }
 
+  // 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,
+      const data_reduction_proxy::DataReductionProxyParams* params,
+      net::ProxyInfo* result)> OnResolveProxyHandler;

[mmenke, 2014/07/07 20:21:59]

nit:  Per Google style guide, typedefs (and enums) go first.

[rcs, 2014/07/07 22:08:49]

Done.

+
+  void set_on_resolve_proxy_handler(OnResolveProxyHandler* handler) {
+    on_resolve_proxy_handler_ = handler;
+  }
+
   // Adds the Client Hints header to HTTP requests.
   void SetEnableClientHints();
 
@@ -178,6 +191,8 @@ 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;
@@ -280,6 +295,8 @@ class ChromeNetworkDelegate : public net::NetworkDelegate {
   data_reduction_proxy::DataReductionProxyAuthRequestHandler*
   data_reduction_proxy_auth_request_handler_;
 
+  OnResolveProxyHandler* on_resolve_proxy_handler_;

[mmenke, 2014/07/07 20:21:59]

Suggest not making this a pointer.  Callbacks have a method...is_empty(), I
believe (Or maybe is_null() or is_valid() or somesuch).

As-is, this is perfectly safe, just keeping a pointer to a callback seems a bit
ugly to me.

[rcs, 2014/07/07 22:08:49]

Done.

+
   DISALLOW_COPY_AND_ASSIGN(ChromeNetworkDelegate);
 };