Cleanup the Win overlapped reads vs. non-blocking reads by removing the overlapped read code path

chrome/browser/chrome_browser_field_trials_desktop.cc

 // Copyright 2013 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/chrome_browser_field_trials_desktop.h"
 
 #include <string>
 
 #include "apps/field_trial_names.h"
 #include "apps/pref_names.h"
 #include "base/command_line.h"
 #include "base/metrics/field_trial.h"
 #include "base/prefs/pref_service.h"
 #include "base/strings/string_util.h"
 #include "chrome/browser/auto_launch_trial.h"
 #include "chrome/browser/google/google_util.h"
 #include "chrome/browser/gpu/chrome_gpu_util.h"
 #include "chrome/browser/omnibox/omnibox_field_trial.h"
 #include "chrome/browser/prerender/prerender_field_trial.h"
 #include "chrome/browser/profiles/profiles_state.h"
 #include "chrome/browser/safe_browsing/safe_browsing_blocking_page.h"
 #include "chrome/browser/ui/sync/one_click_signin_helper.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/chrome_version_info.h"
 #include "chrome/common/metrics/variations/variations_util.h"
 #include "content/public/common/content_constants.h"
 #include "net/spdy/spdy_session.h"
 #include "ui/base/layout.h"
 
-#if defined(OS_WIN)
-#include "net/socket/tcp_client_socket_win.h"
-#endif  // defined(OS_WIN)
-
 namespace chrome {
 
 namespace {
 
 void SetupAppLauncherFieldTrial(PrefService* local_state) {
   if (base::FieldTrialList::FindFullName(apps::kLauncherPromoTrialName) ==
       apps::kResetShowLauncherPromoPrefGroupName) {
     local_state->SetBoolean(apps::prefs::kShowAppLauncherPromo, true);
   }
 }
@@ skipping 67 matching lines @@
           base::FieldTrial::SESSION_RANDOMIZED, NULL));
   trial->AppendGroup("ControlA", sensitivity_analysis_probability);
   trial->AppendGroup("ControlB", sensitivity_analysis_probability);
   trial->AppendGroup("100A", sensitivity_analysis_probability);
   trial->AppendGroup("100B", sensitivity_analysis_probability);
   trial->AppendGroup("200A", sensitivity_analysis_probability);
   trial->AppendGroup("200B", sensitivity_analysis_probability);
   // TODO(gavinp,rvargas): Re-add 400 group to field trial if results justify.
 }
 
-void WindowsOverlappedTCPReadsFieldTrial(
-    const CommandLine& parsed_command_line) {
-#if defined(OS_WIN)
-  if (parsed_command_line.HasSwitch(switches::kOverlappedRead)) {
-    std::string option =
-        parsed_command_line.GetSwitchValueASCII(switches::kOverlappedRead);
-    if (LowerCaseEqualsASCII(option, "off"))
-      net::TCPClientSocketWin::DisableOverlappedReads();
-  } else {
-    const base::FieldTrial::Probability kDivisor = 2;  // 1 in 2 chance
-    const base::FieldTrial::Probability kOverlappedReadProbability = 1;
-    scoped_refptr<base::FieldTrial> overlapped_reads_trial(
-        base::FieldTrialList::FactoryGetFieldTrial(
-            "OverlappedReadImpact", kDivisor, "OverlappedReadEnabled",
-            2013, 6, 1, base::FieldTrial::SESSION_RANDOMIZED, NULL));
-    int overlapped_reads_disabled_group =
-        overlapped_reads_trial->AppendGroup("OverlappedReadDisabled",
-                                            kOverlappedReadProbability);
-    int assigned_group = overlapped_reads_trial->group();
-    if (assigned_group == overlapped_reads_disabled_group)
-      net::TCPClientSocketWin::DisableOverlappedReads();
-  }
-#endif
-}
-
 void SetupLowLatencyFlashAudioFieldTrial() {
   scoped_refptr<base::FieldTrial> trial(
       base::FieldTrialList::FactoryGetFieldTrial(
           content::kLowLatencyFlashAudioFieldTrialName, 100, "Standard",
           2013, 9, 1, base::FieldTrial::SESSION_RANDOMIZED, NULL));
 
   // Trial is enabled for dev / beta / canary users only.
   if (chrome::VersionInfo::GetChannel() != chrome::VersionInfo::CHANNEL_STABLE)
     trial->AppendGroup(content::kLowLatencyFlashAudioFieldTrialEnabledName, 25);
 }
 
 }  // namespace
 
 void SetupDesktopFieldTrials(const CommandLine& parsed_command_line,
                              const base::Time& install_time,
                              PrefService* local_state) {
   prerender::ConfigurePrefetchAndPrerender(parsed_command_line);
   AutoLaunchChromeFieldTrial();
   gpu_util::InitializeCompositingFieldTrial();
   OmniboxFieldTrial::ActivateStaticTrials();
   SetupInfiniteCacheFieldTrial();
   SetupCacheSensitivityAnalysisFieldTrial();
   DisableShowProfileSwitcherTrialIfNecessary();
-  WindowsOverlappedTCPReadsFieldTrial(parsed_command_line);
   SetupAppLauncherFieldTrial(local_state);
   SetupLowLatencyFlashAudioFieldTrial();
 }
 
 }  // namespace chrome