Construct a field trial to see if HIGH or MEDIUM memory model "works better"...

chrome/browser/browser_process_impl.cc

 // Copyright (c) 2006-2008 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_process_impl.h"
 
 #include "base/command_line.h"
+#include "base/path_service.h"
 #include "base/thread.h"
-#include "base/path_service.h"
 #include "chrome/browser/automation/automation_provider_list.h"
+#include "chrome/browser/browser_trial.h"
 #include "chrome/browser/chrome_thread.h"
 #include "chrome/browser/download/download_file.h"
 #include "chrome/browser/download/save_file_manager.h"
 #include "chrome/browser/google_url_tracker.h"
 #include "chrome/browser/icon_manager.h"
 #include "chrome/browser/metrics_service.h"
 #include "chrome/browser/plugin_service.h"
 #include "chrome/browser/printing/print_job_manager.h"
 #include "chrome/browser/profile_manager.h"
 #include "chrome/browser/render_process_host.h"
@@ skipping 87 matching lines @@
   if (command_line.HasSwitch(switches::kMemoryModel)) {
     std::wstring model = command_line.GetSwitchValue(switches::kMemoryModel);
     if (!model.empty()) {
       if (model == L"high")
         memory_model_ = HIGH_MEMORY_MODEL;
       else if (model == L"low")
         memory_model_ = LOW_MEMORY_MODEL;
       else if (model == L"medium")
         memory_model_ = MEDIUM_MEMORY_MODEL;
     }
+  } else {
+    // Randomly choose what memory model to use.
+    const double probability = 0.5;
+    FieldTrial* trial(new FieldTrial(BrowserTrial::kMemoryModelFieldTrial,
+                                     probability));
+    DCHECK(FieldTrialList::Find(BrowserTrial::kMemoryModelFieldTrial) == trial);
+    if (trial->boolean_value())
+      memory_model_ = HIGH_MEMORY_MODEL;
+    else
+      memory_model_ = MEDIUM_MEMORY_MODEL;
   }
 
   suspend_controller_ = new SuspendController();
 
   shutdown_event_ = ::CreateEvent(NULL, TRUE, FALSE, NULL);
 }
 
 BrowserProcessImpl::~BrowserProcessImpl() {
   // Delete the AutomationProviderList before NotificationService,
   // since it may try to unregister notifications
@@ skipping 217 matching lines @@
       new views::AcceleratorHandler);
   accelerator_handler_.swap(accelerator_handler);
 }
 
 void BrowserProcessImpl::CreateGoogleURLTracker() {
   DCHECK(google_url_tracker_.get() == NULL);
   scoped_ptr<GoogleURLTracker> google_url_tracker(new GoogleURLTracker);
   google_url_tracker_.swap(google_url_tracker);
 }