Add Finch experiment for selectively bypassing proxies.

net/proxy/proxy_service.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/proxy/proxy_service.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
@@ skipping 753 matching lines @@
         base::Bind(&PacRequest::QueryComplete, base::Unretained(this)),
         &resolve_job_, net_log_);
   }
 
   bool is_started() const {
     // Note that !! casts to bool. (VS gives a warning otherwise).
     return !!resolve_job_;
   }
 
   void StartAndCompleteCheckingForSynchronous() {
-    int rv = service_->TryToCompleteSynchronously(url_, results_);
+    int rv = service_->TryToCompleteSynchronously(url_, 0, results_);
     if (rv == ERR_IO_PENDING)
       rv = Start();
     if (rv != ERR_IO_PENDING)
       QueryComplete(rv);
   }
 
   void CancelResolveJob() {
     DCHECK(is_started());
     // The request may already be running in the resolver.
     resolver()->CancelRequest(resolve_job_);
@@ skipping 85 matching lines @@
   BoundNetLog net_log_;
   // Time when the PAC is started.  Cached here since resetting ProxyInfo also
   // clears the proxy times.
   TimeTicks proxy_resolve_start_time_;
 };
 
 // ProxyService ---------------------------------------------------------------
 
 ProxyService::ProxyService(ProxyConfigService* config_service,
                            ProxyResolver* resolver,
+                           NetworkDelegate* network_delegate,
                            NetLog* net_log)
     : resolver_(resolver),
       next_config_id_(1),
-      current_state_(STATE_NONE) ,
+      current_state_(STATE_NONE),
+      network_delegate_(network_delegate),
       net_log_(net_log),
       stall_proxy_auto_config_delay_(TimeDelta::FromMilliseconds(
           kDelayAfterNetworkChangesMs)),
       quick_check_enabled_(true) {
   NetworkChangeNotifier::AddIPAddressObserver(this);
   NetworkChangeNotifier::AddDNSObserver(this);
   ResetConfigService(config_service);
 }
 
 // static
 ProxyService* ProxyService::CreateUsingSystemProxyResolver(
     ProxyConfigService* proxy_config_service,
     size_t num_pac_threads,
     NetLog* net_log) {
   DCHECK(proxy_config_service);
 
   if (!ProxyResolverFactoryForSystem::IsSupported()) {
     LOG(WARNING) << "PAC support disabled because there is no "
                     "system implementation";
     return CreateWithoutProxyResolver(proxy_config_service, net_log);
   }
 
   if (num_pac_threads == 0)
     num_pac_threads = kDefaultNumPacThreads;
 
   ProxyResolver* proxy_resolver = new MultiThreadedProxyResolver(
       new ProxyResolverFactoryForSystem(), num_pac_threads);
 
-  return new ProxyService(proxy_config_service, proxy_resolver, net_log);
+  return new ProxyService(proxy_config_service, proxy_resolver, NULL, net_log);
 }
 
 // static
 ProxyService* ProxyService::CreateWithoutProxyResolver(
     ProxyConfigService* proxy_config_service,
     NetLog* net_log) {
   return new ProxyService(proxy_config_service,
                           new ProxyResolverNull(),
+                          NULL,
                           net_log);
 }
 
 // static
 ProxyService* ProxyService::CreateFixed(const ProxyConfig& pc) {
   // TODO(eroman): This isn't quite right, won't work if |pc| specifies
   //               a PAC script.
   return CreateUsingSystemProxyResolver(new ProxyConfigServiceFixed(pc),
                                         0, NULL);
 }
 
 // static
 ProxyService* ProxyService::CreateFixed(const std::string& proxy) {
   net::ProxyConfig proxy_config;
   proxy_config.proxy_rules().ParseFromString(proxy);
   return ProxyService::CreateFixed(proxy_config);
 }
 
 // static
 ProxyService* ProxyService::CreateDirect() {
   return CreateDirectWithNetLog(NULL);
 }
 
 ProxyService* ProxyService::CreateDirectWithNetLog(NetLog* net_log) {
   // Use direct connections.
   return new ProxyService(new ProxyConfigServiceDirect, new ProxyResolverNull,
-                          net_log);
+                          NULL, net_log);
 }
 
 // static
 ProxyService* ProxyService::CreateFixedFromPacResult(
     const std::string& pac_string) {
 
   // We need the settings to contain an "automatic" setting, otherwise the
   // ProxyResolver dependency we give it will never be used.
   scoped_ptr<ProxyConfigService> proxy_config_service(
       new ProxyConfigServiceFixed(ProxyConfig::CreateAutoDetect()));
 
   scoped_ptr<ProxyResolver> proxy_resolver(
       new ProxyResolverFromPacString(pac_string));
 
   return new ProxyService(proxy_config_service.release(),
                           proxy_resolver.release(),
-                          NULL);
+                          NULL, NULL);
 }
 
 int ProxyService::ResolveProxy(const GURL& raw_url,
+                               int load_flags,
                                ProxyInfo* result,
                                const net::CompletionCallback& callback,
                                PacRequest** pac_request,
                                const BoundNetLog& net_log) {
   DCHECK(CalledOnValidThread());
   DCHECK(!callback.is_null());
 
   net_log.BeginEvent(NetLog::TYPE_PROXY_SERVICE);
 
   // Notify our polling-based dependencies that a resolve is taking place.
   // This way they can schedule their polls in response to network activity.
   config_service_->OnLazyPoll();
   if (script_poller_.get())
      script_poller_->OnLazyPoll();
 
   if (current_state_ == STATE_NONE)
     ApplyProxyConfigIfAvailable();
 
   // Strip away any reference fragments and the username/password, as they
   // are not relevant to proxy resolution.
   GURL url = SimplifyUrlForRequest(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, result);
   if (rv != ERR_IO_PENDING)
     return DidFinishResolvingProxy(result, rv, net_log);
 
+  // TODO(rcs): add load_flags to PacRequest.

[mmenke, 2014/06/27 18:59:35]

Flywheel requests always go through a PAC currently, don't they?

[rcs, 2014/06/28 03:53:38]

I ran this (a few days) without adding load_flags to PacRequest, and verified
(via netlog and console logging) that it's bypassing flywheel correctly.

Will verify again once I'm back in Seattle

[rcs, 2014/06/28 04:01:04]

*a few days ago

[rcs, 2014/06/30 19:46:31]

I verified that data compression proxy requests do *not* go through PacRequests.
bengr@ mentioned that our requests used to go through PacRequests, but no
longer.

   scoped_refptr<PacRequest> req(
       new PacRequest(this, url, result, callback, net_log));
 
   if (current_state_ == STATE_READY) {
     // Start the resolve request.
     rv = req->Start();
     if (rv != ERR_IO_PENDING)
       return req->QueryDidComplete(rv);
   } else {
     req->net_log()->BeginEvent(NetLog::TYPE_PROXY_SERVICE_WAITING_FOR_INIT_PAC);
   }
 
   DCHECK_EQ(ERR_IO_PENDING, rv);
   DCHECK(!ContainsPendingRequest(req.get()));
   pending_requests_.push_back(req);
 
   // Completion will be notified through |callback|, unless the caller cancels
   // the request using |pac_request|.
   if (pac_request)
     *pac_request = req.get();
   return rv;  // ERR_IO_PENDING
 }
 
 int ProxyService::TryToCompleteSynchronously(const GURL& url,
+                                             int load_flags,
                                              ProxyInfo* result) {
   DCHECK_NE(STATE_NONE, current_state_);
 
   if (current_state_ != STATE_READY)
     return ERR_IO_PENDING;  // Still initializing.
 
   DCHECK_NE(config_.id(), ProxyConfig::kInvalidConfigID);
 
   // If it was impossible to fetch or parse the PAC script, we cannot complete
   // the request here and bail out.
   if (permanent_error_ != OK)
     return permanent_error_;
 
   if (config_.HasAutomaticSettings())
     return ERR_IO_PENDING;  // Must submit the request to the proxy resolver.
 
   // Use the manual proxy settings.
   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);
+  }
+
   return OK;
 }
 
 ProxyService::~ProxyService() {
   NetworkChangeNotifier::RemoveIPAddressObserver(this);
   NetworkChangeNotifier::RemoveDNSObserver(this);
   config_service_->RemoveObserver(this);
 
   // Cancel any inprogress requests.
   for (PendingRequests::iterator it = pending_requests_.begin();
@@ skipping 126 matching lines @@
   // Check to see if we have a new config since ResolveProxy was called.  We
   // want to re-run ResolveProxy in two cases: 1) we have a new config, or 2) a
   // direct connection failed and we never tried the current config.
 
   bool re_resolve = result->config_id_ != config_.id();
 
   if (re_resolve) {
     // 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, net_log);
   }
 
 #if defined(SPDY_PROXY_AUTH_ORIGIN)
   if (result->proxy_server().isDataReductionProxy()) {
     RecordDataReductionProxyBypassInfo(
         true, result->proxy_server(), ERROR_BYPASS);
     RecordDataReductionProxyBypassOnNetworkError(
         true, result->proxy_server(), net_error);
   } else if (result->proxy_server().isDataReductionProxyFallback()) {
     RecordDataReductionProxyBypassInfo(
@@ skipping 419 matching lines @@
     *proxy_info = proxy_info_;
   }
   return result_;
 }
 
 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, net_log);
   if (result_ != net::ERR_IO_PENDING) {
     OnCompletion(result_);
   }
 }
 
 void SyncProxyServiceHelper::StartAsyncReconsider(const GURL& url,
                                                   int net_error,
                                                   const BoundNetLog& net_log) {
   result_ = proxy_service_->ReconsiderProxyAfterError(
       url, net_error, &proxy_info_, callback_, NULL, net_log);
   if (result_ != net::ERR_IO_PENDING) {
     OnCompletion(result_);
   }
 }
 
 void SyncProxyServiceHelper::OnCompletion(int rv) {
   result_ = rv;
   event_.Signal();
 }
 
 }  // namespace net