Remove trace of MouseEventPreconnect field trial.

chrome/browser/chrome_browser_field_trials.cc

 // Copyright (c) 2012 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.h"
 
 #include <string>
 
 #include "base/command_line.h"
 #include "base/metrics/field_trial.h"
@@ skipping 29 matching lines @@
   chrome::SetupMobileFieldTrials(parsed_command_line_);
 #else
   chrome::SetupDesktopFieldTrials(parsed_command_line_);
 #endif
 }
 
 void ChromeBrowserFieldTrials::InstantiateDynamicTrials() {
   // The following trials are used from renderer process.
   // Mark here so they will be sync-ed.
   base::FieldTrialList::FindValue("CLD1VsCLD2");
-  base::FieldTrialList::FindValue("MouseEventPreconnect");
   base::FieldTrialList::FindValue("DisplayList2dCanvas");
   // Activate the autocomplete dynamic field trials.
   OmniboxFieldTrial::ActivateDynamicTrials();
 }