Introduce a policy to control the maximal number of connections per proxy server.

chrome/browser/net/net_pref_observer.cc

Index: chrome/browser/net/net_pref_observer.cc
diff --git a/chrome/browser/net/net_pref_observer.cc b/chrome/browser/net/net_pref_observer.cc
index 8a0d08e72032152cd7c1d5923063ba71e0b261d0..68a22ccedfd645fedd519cdcada114252372a0ff 100644
--- a/chrome/browser/net/net_pref_observer.cc
+++ b/chrome/browser/net/net_pref_observer.cc
@@ -15,6 +15,7 @@
 #include "content/common/notification_type.h"
 #include "content/common/notification_details.h"
 #include "net/http/http_stream_factory.h"
+#include "net/socket/client_socket_pool_manager.h"
 #include "net/url_request/url_request_throttler_manager.h"
 
 namespace {
@@ -37,6 +38,7 @@ NetPrefObserver::NetPrefObserver(PrefService* prefs,
                                    this);
   spdy_disabled_.Init(prefs::kDisableSpdy, prefs, this);
   http_throttling_enabled_.Init(prefs::kHttpThrottlingEnabled, prefs, this);
+  max_connections_per_proxy_.Init(prefs::kMaxConnectionsPerProxy, prefs, this);
 
   ApplySettings(NULL);
 }
@@ -68,6 +70,14 @@ void NetPrefObserver::ApplySettings(const std::string* pref_name) {
         NewRunnableFunction(SetEnforceThrottlingOnThrottlerManager,
                             *http_throttling_enabled_));
   }
+
+  if (!pref_name || *pref_name == prefs::kMaxConnectionsPerProxy) {

[willchan no longer on Chromium, 2011/06/29 22:54:55]

There are a few issues here. First, this is only safe to run on the UI thread
before the IO thread has started. Otherwise, it needs to run on the IO thread.
Also, it doesn't work dynamically. The global is only read when creating the
socket pools, which only happens when a profile is created. Is that ok?

[pastarmovj, 2011/07/01 18:52:44]

Ok i removed the dynamic marking from the policy and the observer for it. So it
will only be set once on browser boot.

+    // Make sure the value is not greater than 100 and nor smaller than the
+    // maximal number of connections allowed per group.
+    net::ClientSocketPoolManager::set_max_sockets_per_proxy_server(
+        std::max(std::min(*max_connections_per_proxy_, 100),
+                 net::ClientSocketPoolManager::max_sockets_per_group()));
+  }
 }
 
 // static
@@ -84,7 +94,9 @@ void NetPrefObserver::RegisterPrefs(PrefService* prefs) {
   prefs->RegisterBooleanPref(prefs::kHttpThrottlingMayExperiment,
                              true,
                              PrefService::UNSYNCABLE_PREF);
-
+  prefs->RegisterIntegerPref(prefs::kMaxConnectionsPerProxy,
+                             32,

[willchan no longer on Chromium, 2011/06/29 22:54:55]

This should probably use a default that is read from net/. Perhaps you should
take the value of 32 from client_socket_pool_manager.cc and make it a global
named constant, so it can be used here.

[pastarmovj, 2011/07/01 18:52:44]

Done.

+                             PrefService::UNSYNCABLE_PREF);
   // This is the earliest point at which we can set up the trial, as
   // it relies on prefs for parameterization.
   CreateHttpThrottlingTrial(prefs);