Add Finch experiment for selectively bypassing proxies.

net/proxy/proxy_service.cc

Index: net/proxy/proxy_service.cc
diff --git a/net/proxy/proxy_service.cc b/net/proxy/proxy_service.cc
index c5cd6ac3354c6630f64426dd938a29d1a00e7ee3..e1046c1b6d25d47d4b96ef70e2fc460357358d9f 100644
--- a/net/proxy/proxy_service.cc
+++ b/net/proxy/proxy_service.cc
@@ -771,7 +771,7 @@ class ProxyService::PacRequest
   }
 
   void StartAndCompleteCheckingForSynchronous() {
-    int rv = service_->TryToCompleteSynchronously(url_, results_);
+    int rv = service_->TryToCompleteSynchronously(url_, 0, NULL, results_);

[mmenke, 2014/07/01 19:45:12]

Rather than using 0 for load flags, should use LOAD_NORMAL (Goes for all files)

[rcs, 2014/07/02 00:56:20]

Done.

     if (rv == ERR_IO_PENDING)
       rv = Start();
     if (rv != ERR_IO_PENDING)
@@ -880,7 +880,7 @@ ProxyService::ProxyService(ProxyConfigService* config_service,
                            NetLog* net_log)
     : resolver_(resolver),
       next_config_id_(1),
-      current_state_(STATE_NONE) ,
+      current_state_(STATE_NONE),
       net_log_(net_log),
       stall_proxy_auto_config_delay_(TimeDelta::FromMilliseconds(
           kDelayAfterNetworkChangesMs)),
@@ -965,9 +965,11 @@ ProxyService* ProxyService::CreateFixedFromPacResult(
 }
 
 int ProxyService::ResolveProxy(const GURL& raw_url,
+                               int load_flags,
                                ProxyInfo* result,
                                const net::CompletionCallback& callback,
                                PacRequest** pac_request,
+                               NetworkDelegate* network_delegate,
                                const BoundNetLog& net_log) {
   DCHECK(CalledOnValidThread());
   DCHECK(!callback.is_null());
@@ -989,10 +991,12 @@ int ProxyService::ResolveProxy(const GURL& raw_url,
 
   // Check if the request can be completed right away. (This is the case when
   // using a direct connection for example).
-  int rv = TryToCompleteSynchronously(url, result);
+  int rv = TryToCompleteSynchronously(url, load_flags,
+                                      network_delegate, result);
   if (rv != ERR_IO_PENDING)
     return DidFinishResolvingProxy(result, rv, net_log);
 
+  // TODO(rcs): add load_flags and network_delegate to PacRequest.

[mmenke, 2014/07/01 19:45:12]

Since we aren't using flywheel with PACs, and are planning to get rid of this
code when we create a flywheel proxy service, I don't think we need this TODO. 
Instead, can just add a comment to the modified PAC calls that the data
reduction proxy isn't used with PACs.

[rcs, 2014/07/02 00:56:20]

Done.

   scoped_refptr<PacRequest> req(
       new PacRequest(this, url, result, callback, net_log));
 
@@ -1017,6 +1021,8 @@ int ProxyService::ResolveProxy(const GURL& raw_url,
 }
 
 int ProxyService::TryToCompleteSynchronously(const GURL& url,
+                                             int load_flags,
+                                             NetworkDelegate* network_delegate,
                                              ProxyInfo* result) {
   DCHECK_NE(STATE_NONE, current_state_);
 
@@ -1037,6 +1043,13 @@ int ProxyService::TryToCompleteSynchronously(const GURL& url,
   config_.proxy_rules().Apply(url, result);
   result->config_source_ = config_.source();
   result->config_id_ = config_.id();
+
+  // Allow the network delegate to interpose on the resolution decision,
+  // possibly modifying the ProxyInfo.
+  if (network_delegate) {
+    network_delegate->NotifyResolveProxy(url, load_flags, result);
+  }

[mmenke, 2014/07/01 19:45:12]

nit:  To be consistent with the rest of the code in this file, don't use braces
here.

[rcs, 2014/07/02 00:56:20]

Done.

+
   return OK;
 }
 
@@ -1183,7 +1196,7 @@ int ProxyService::ReconsiderProxyAfterError(const GURL& url,
     // If we have a new config or the config was never tried, we delete the
     // list of bad proxies and we try again.
     proxy_retry_info_.clear();
-    return ResolveProxy(url, result, callback, pac_request, net_log);
+    return ResolveProxy(url, 0, result, callback, pac_request, NULL, net_log);
   }
 
 #if defined(SPDY_PROXY_AUTH_ORIGIN)
@@ -1623,7 +1636,7 @@ SyncProxyServiceHelper::~SyncProxyServiceHelper() {}
 void SyncProxyServiceHelper::StartAsyncResolve(const GURL& url,
                                                const BoundNetLog& net_log) {
   result_ = proxy_service_->ResolveProxy(
-      url, &proxy_info_, callback_, NULL, net_log);
+      url, 0, &proxy_info_, callback_, NULL, NULL, net_log);
   if (result_ != net::ERR_IO_PENDING) {
     OnCompletion(result_);
   }