Refactor declaration order for 2 A/B tests....

chrome/browser/browser_main.cc

 // Copyright (c) 2010 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 "chrome/browser/browser_main.h"
 
 #include <algorithm>
 #include <string>
 #include <vector>
 
@@ skipping 171 matching lines @@
 // mechanisms.
 void BrowserMainParts::ConnectionFieldTrial() {
   const FieldTrial::Probability kConnectDivisor = 100;
   const FieldTrial::Probability kConnectProbability = 20;  // 20% probability
 
   scoped_refptr<FieldTrial> connect_trial =
       new FieldTrial("ConnCountImpact", kConnectDivisor);
 
   const int connect_5 = connect_trial->AppendGroup("_conn_count_5",
                                                    kConnectProbability);
-  const int connect_6 = connect_trial->AppendGroup("_conn_count_6",
-                                                   kConnectProbability);
   const int connect_7 = connect_trial->AppendGroup("_conn_count_7",
                                                    kConnectProbability);
   const int connect_8 = connect_trial->AppendGroup("_conn_count_8",
                                                    kConnectProbability);
   const int connect_9 = connect_trial->AppendGroup("_conn_count_9",
+                                                   kConnectProbability);
+  // This (6) is the current default value. Having this group declared here
+  // makes it straightforward to modify |kConnectProbability| such that the same
+  // probability value will be assigned to all the other groups, while
+  // preserving the remainder of the of probability space to the default value.
+  const int connect_6 = connect_trial->AppendGroup("_conn_count_6",
       FieldTrial::kAllRemainingProbability);
 
   const int connect_trial_group = connect_trial->group();
 
   if (connect_trial_group == connect_5) {
     net::HttpNetworkSession::set_max_sockets_per_group(5);
   } else if (connect_trial_group == connect_6) {
-    // This (6) is the current default value.
     net::HttpNetworkSession::set_max_sockets_per_group(6);
   } else if (connect_trial_group == connect_7) {
     net::HttpNetworkSession::set_max_sockets_per_group(7);
   } else if (connect_trial_group == connect_8) {
     net::HttpNetworkSession::set_max_sockets_per_group(8);
   } else if (connect_trial_group == connect_9) {
     net::HttpNetworkSession::set_max_sockets_per_group(9);
   } else {
     NOTREACHED();
   }
 }
 
 // A/B test for determining a value for unused socket timeout. Currently the
 // timeout defaults to 10 seconds. Having this value set too low won't allow us
 // to take advantage of idle sockets. Setting it to too high could possibly
 // result in more ERR_CONNECT_RESETs, requiring one RTT to receive the RST
 // packet and possibly another RTT to re-establish the connection.
 void BrowserMainParts::SocketTimeoutFieldTrial() {
   const FieldTrial::Probability kIdleSocketTimeoutDivisor = 100;
   // 25% probability
   const FieldTrial::Probability kSocketTimeoutProbability = 25;
 
   scoped_refptr<FieldTrial> socket_timeout_trial =
       new FieldTrial("IdleSktToImpact", kIdleSocketTimeoutDivisor);
 
   const int socket_timeout_5 =
       socket_timeout_trial->AppendGroup("_idle_timeout_5",
                                         kSocketTimeoutProbability);
-  const int socket_timeout_10 =
-      socket_timeout_trial->AppendGroup("_idle_timeout_10",
-                                        kSocketTimeoutProbability);
   const int socket_timeout_20 =
       socket_timeout_trial->AppendGroup("_idle_timeout_20",
                                         kSocketTimeoutProbability);
   const int socket_timeout_60 =
       socket_timeout_trial->AppendGroup("_idle_timeout_60",
+                                        kSocketTimeoutProbability);
+  // This (10 seconds) is the current default value. Declaring it at the end
+  // allows for assigning the remainder of the probability space to it; which
+  // will make it to modify this value (by changing |kSocketTimeoutProbability|)
+  // down the road if we see the need to, while the remaining groups are
+  // are assigned an equal share of the probability space.
+  const int socket_timeout_10 =
+      socket_timeout_trial->AppendGroup("_idle_timeout_10",
                                         FieldTrial::kAllRemainingProbability);
 
   const int idle_to_trial_group = socket_timeout_trial->group();
 
   if (idle_to_trial_group == socket_timeout_5) {
     net::ClientSocketPool::set_unused_idle_socket_timeout(5);
   } else if (idle_to_trial_group == socket_timeout_10) {
-    // This (10 seconds) is the current default value.
     net::ClientSocketPool::set_unused_idle_socket_timeout(10);
   } else if (idle_to_trial_group == socket_timeout_20) {
     net::ClientSocketPool::set_unused_idle_socket_timeout(20);
   } else if (idle_to_trial_group == socket_timeout_60) {
     net::ClientSocketPool::set_unused_idle_socket_timeout(60);
   } else {
     NOTREACHED();
   }
 }
 
@@ skipping 1015 matching lines @@
 
   metrics->Stop();
 
   // browser_shutdown takes care of deleting browser_process, so we need to
   // release it.
   ignore_result(browser_process.release());
   browser_shutdown::Shutdown();
 
   return result_code;
 }