2 experiments: DNS prefetch limit concurrency: TCP split a packet

chrome/browser/browser_main.cc

Index: chrome/browser/browser_main.cc
===================================================================
--- chrome/browser/browser_main.cc	(revision 42146)
+++ chrome/browser/browser_main.cc	(working copy)
@@ -417,9 +417,23 @@
   SystemMonitor system_monitor;
   HighResolutionTimerManager hi_res_timer_manager;
 
-  // Initialize statistical testing infrastructure.
+  // Initialize statistical testing infrastructure for entire browser.
   FieldTrialList field_trial;
 
+  // Set up a field trial to see if splitting the first transmitted packet helps
+  // with latency.
+  {
+    FieldTrial::Probability kDivisor = 100;
+    FieldTrial* trial = new FieldTrial("PacketSplit", kDivisor);
+    // For each option (i.e., non-default), we have a fixed probability.
+    FieldTrial::Probability kProbabilityPerGroup = 10;  // 10% probability.
+    int split = trial->AppendGroup("_first_packet_split", kProbabilityPerGroup);
+    DCHECK_EQ(split, 0);
+    int intact = trial->AppendGroup("_first_packet_intact",
+                                    FieldTrial::kAllRemainingProbability);
+    DCHECK_EQ(intact, 1);
+  }
+
   std::wstring app_name = chrome::kBrowserAppName;
   std::string thread_name_string = WideToASCII(app_name + L"_BrowserMain");